WorldWideScience

Sample records for stretching region shows

  1. Acute effect of stretching one leg on regional arterial stiffness in young men.

    Science.gov (United States)

    Yamato, Yosuke; Hasegawa, Natsuki; Fujie, Shumpei; Ogoh, Shigehiko; Iemitsu, Motoyuki

    2017-06-01

    Our previous study demonstrated that a single bout of stretching exercises acutely reduced arterial stiffness. We hypothesized that this acute vascular response is due to regional mechanical stimulation of the peripheral arteries. To test this hypothesis, we examined the effect of a single bout of passive one leg stretching on arterial stiffness, comparing the stretched and the non-stretched leg in the same subject. Twenty-five healthy young men (20.9 ± 0.3 years, 172.5 ± 1.4 cm, 64.1 ± 1.2 kg) volunteered for the study. Subjects underwent a passive calf stretching on one leg (six repetitions of 30-s static stretch with a 10-s recovery). Pulse wave velocity (PWV, an index of arterial stiffness), blood pressure (BP), and heart rate (HR) were measured before and immediately, 15, and 30 min after the stretching. Femoral-ankle PWV (faPWV) in the stretched leg was significantly decreased from baseline (835.0 ± 15.9 cm/s) to immediately (802.9 ± 16.8 cm/s, P leg was not significantly altered at any time. Brachial-ankle PWV (baPWV) also showed similar responses with faPWV, but this response was not significant. Additionally, the passive stretching did not alter carotid-femoral PWV (cfPWV). These results suggest that mechanical stimulation to peripheral arteries as induced by static passive stretch may modulate arterial wall properties directly, rather than resulting in a systemic effect.

  2. Regional Climate Simulation with a Variable Resolution Stretched Grid GCM: The Regional Down-Scaling Effects

    Science.gov (United States)

    Fox-Rabinovitz, Michael S.; Takacs, Lawrence L.; Suarez, Max; Sawyer, William; Govindaraju, Ravi C.

    1999-01-01

    The results obtained with the variable resolution stretched grid (SG) GEOS GCM (Goddard Earth Observing System General Circulation Models) are discussed, with the emphasis on the regional down-scaling effects and their dependence on the stretched grid design and parameters. A variable resolution SG-GCM and SG-DAS using a global stretched grid with fine resolution over an area of interest, is a viable new approach to REGIONAL and subregional CLIMATE studies and applications. The stretched grid approach is an ideal tool for representing regional to global scale interactions. It is an alternative to the widely used nested grid approach introduced a decade ago as a pioneering step in regional climate modeling. The GEOS SG-GCM is used for simulations of the anomalous U.S. climate events of 1988 drought and 1993 flood, with enhanced regional resolution. The height low level jet, precipitation and other diagnostic patterns are successfully simulated and show the efficient down-scaling over the area of interest the U.S. An imitation of the nested grid approach is performed using the developed SG-DAS (Data Assimilation System) that incorporates the SG-GCM. The SG-DAS is run with withholding data over the area of interest. The design immitates the nested grid framework with boundary conditions provided from analyses. No boundary condition buffer is needed for the case due to the global domain of integration used for the SG-GCM and SG-DAS. The experiments based on the newly developed versions of the GEOS SG-GCM and SG-DAS, with finer 0.5 degree (and higher) regional resolution, are briefly discussed. The major aspects of parallelization of the SG-GCM code are outlined. The KEY OBJECTIVES of the study are: 1) obtaining an efficient DOWN-SCALING over the area of interest with fine and very fine resolution; 2) providing CONSISTENT interactions between regional and global scales including the consistent representation of regional ENERGY and WATER BALANCES; 3) providing a high

  3. Simulation of Anomalous Regional Climate Events with a Variable Resolution Stretched Grid GCM

    Science.gov (United States)

    Fox-Rabinovitz, Michael S.

    1999-01-01

    The stretched-grid approach provides an efficient down-scaling and consistent interactions between global and regional scales due to using one variable-resolution model for integrations. It is a workable alternative to the widely used nested-grid approach introduced over a decade ago as a pioneering step in regional climate modeling. A variable-resolution General Circulation Model (GCM) employing a stretched grid, with enhanced resolution over the US as the area of interest, is used for simulating two anomalous regional climate events, the US summer drought of 1988 and flood of 1993. The special mode of integration using a stretched-grid GCM and data assimilation system is developed that allows for imitating the nested-grid framework. The mode is useful for inter-comparison purposes and for underlining the differences between these two approaches. The 1988 and 1993 integrations are performed for the two month period starting from mid May. Regional resolutions used in most of the experiments is 60 km. The major goal and the result of the study is obtaining the efficient down-scaling over the area of interest. The monthly mean prognostic regional fields for the stretched-grid integrations are remarkably close to those of the verifying analyses. Simulated precipitation patterns are successfully verified against gauge precipitation observations. The impact of finer 40 km regional resolution is investigated for the 1993 integration and an example of recovering subregional precipitation is presented. The obtained results show that the global variable-resolution stretched-grid approach is a viable candidate for regional and subregional climate studies and applications.

  4. Length heteroplasmy of the polyC-polyT-polyC stretch in the dog mtDNA control region.

    Science.gov (United States)

    Verscheure, Sophie; Backeljau, Thierry; Desmyter, Stijn

    2015-09-01

    Previously, the mitochondrial control region of 214 Belgian dogs was sequenced. Analysis of this data indicated length heteroplasmy of the polyT stretch in the polyC-polyT-polyC stretch from positions 16661 to 16674. Nine polyC-polyT-polyC haplotype combinations were observed, consisting of seven major haplotypes (highest signal intensity) combined with minor haplotypes (lower signal intensity) one T shorter than the major haplotype in all but three dogs. The longer the polyT stretch, the smaller was the difference in signal intensity between the major and minor haplotype peaks. Additional sequencing, cloning, and PCR trap experiments were performed to further study the intra-individual variation of this mitochondrial DNA (mtDNA) region. Cloning experiments demonstrated that the proportion of clones displaying the minor haplotypes also increased with the length of the polyT stretch. Clone amplification showed that in vitro polymerase errors might contribute to the length heteroplasmy of polyT stretches with at least 10 Ts. Although major and minor polyC-polyT-polyC haplotypes did not differ intra-individually within and between tissues in this study, interpretation of polyT stretch variation should be handled with care in forensic casework.

  5. A Variable Resolution Stretched Grid General Circulation Model: Regional Climate Simulation

    Science.gov (United States)

    Fox-Rabinovitz, Michael S.; Takacs, Lawrence L.; Govindaraju, Ravi C.; Suarez, Max J.

    2000-01-01

    The development of and results obtained with a variable resolution stretched-grid GCM for the regional climate simulation mode, are presented. A global variable resolution stretched- grid used in the study has enhanced horizontal resolution over the U.S. as the area of interest The stretched-grid approach is an ideal tool for representing regional to global scale interaction& It is an alternative to the widely used nested grid approach introduced over a decade ago as a pioneering step in regional climate modeling. The major results of the study are presented for the successful stretched-grid GCM simulation of the anomalous climate event of the 1988 U.S. summer drought- The straightforward (with no updates) two month simulation is performed with 60 km regional resolution- The major drought fields, patterns and characteristics such as the time averaged 500 hPa heights precipitation and the low level jet over the drought area. appear to be close to the verifying analyses for the stretched-grid simulation- In other words, the stretched-grid GCM provides an efficient down-scaling over the area of interest with enhanced horizontal resolution. It is also shown that the GCM skill is sustained throughout the simulation extended to one year. The developed and tested in a simulation mode stretched-grid GCM is a viable tool for regional and subregional climate studies and applications.

  6. Regional stretch method to measure the elastic and hyperelastic properties of soft materials

    Science.gov (United States)

    Sheng, JunYuan; Guo, HaoYuan; Cao, YanPing; Feng, XiQiao

    2018-02-01

    Characterizing the mechanical properties of soft materials and biological tissues is of great significance for understanding their deformation behaviors. In this paper, a regional stretching method is proposed to measure the elastic and hyperelastic properties of a soft material with an adhesive surface or with the aid of glue. Theoretical and dimensional analyses are performed to investigate the regional stretch problem for soft materials that obey the neo-Hookean model, the Mooney-Rivlin model, or the Arruda-Boyce model. Finite element simulations are made to determine the expressions of the dimensionless functions that correlate the stretch response with the constitutive parameters. Thereby, an inverse approach is established to determine the elastic and hyperelastic properties of the tested materials. The regional stretch method is also compared to the indentation technique. Finally, experiments are performed to demonstrate the effectiveness of the proposed method.

  7. A Variable-Resolution Stretched-Grid General Circulation Model and Data Assimilation System with Multiple Areas of Interest: Studying the Anomalous Regional Climate Events of 1998

    Science.gov (United States)

    Fox-Rabinovitz, Michael S.; Takacs, Lawrence; Govindaraju, Ravi C.; Atlas, Robert (Technical Monitor)

    2002-01-01

    The new stretched-grid design with multiple (four) areas of interest, one at each global quadrant, is implemented into both a stretched-grid GCM (general circulation model) and a stretched-grid data assimilation system (DAS). The four areas of interest include: the U.S./Northern Mexico, the El Nino area/Central South America, India/China, and the Eastern Indian Ocean/Australia. Both the stretched-grid GCM and DAS annual (November 1997 through December 1998) integrations are performed with 50 km regional resolution. The efficient regional down-scaling to mesoscales is obtained for each of the four areas of interest while the consistent interactions between regional and global scales and the high quality of global circulation, are preserved. This is the advantage of the stretched-grid approach. The global variable resolution DAS incorporating the stretched-grid GCM has been developed and tested as an efficient tool for producing regional analyses and diagnostics with enhanced mesoscale resolution. The anomalous regional climate events of 1998 that occurred over the U.S., Mexico, South America, China, India, African Sahel, and Australia are investigated in both simulation and data assimilation modes. Tree assimilated products are also used, along with gauge precipitation data, for validating the simulation results. The obtained results show that the stretched-grid GCM and DAS are capable of producing realistic high quality simulated and assimilated products at mesoscale resolution for regional climate studies and applications.

  8. Regional Climate Simulation with a Variable Resolution Stretch Grid GCM: The 1998 Summer Drought

    Science.gov (United States)

    Fox-Rabinovitz, Michael; Stein, Uri; Takacs, Lawrence; Govindaraju, Ravi; Suarez, Max

    1999-01-01

    The variable resolution stretched grid(SG) GCM based on the Goddard Earth Observing System (GEOS) GCM, has been developed and tested in a regional climate simulation mode. The GEOS SG-GCM is used for simulation of the 1988 summer drought over the U.S. Midwest. Within the stretched grid, the region of interest with a uniform about 60 km resolution is a rectangle over the U.S. Outside the region, the grid intervals increase or stretch with a constant stretching factor (as a geometric progression). The results of two-month simulation for the anomalous climate event of the U.S. drought of 1988, are validated against data analysis fields and diagnostics. The event has been chosen by the Project to Inter-compare Regional Climate Simulations(PIRCS). The efficient regional down-scaling as well as the positive impact of fine regional resolution, are obtained. More specifically, the precipitation, 500 hPa, and low-level jet patterns and characteristics are well represented in the simulation. The SG-concept appeared to be a promising candidate for regional and subregional climate studies and applications.

  9. Regional Climate Simulation Experiments with a Variable Resolution Stretched Grid GCM

    Science.gov (United States)

    Takacs, Lawrence L.; Stein, Uri; Govindaraju, Ravi C.

    1999-01-01

    The variable resolution stretched grid (SG) version of the Goddard Earth Observing System (GEOS) GCM has been recently developed and tested in a regional climate simulation mode. The SG-approach is an alternative to the widely used nested grid approach introduced a decade ago as a pioneering step to regional climate modeling. The region of interest with a uniform about 60 km resolution used in experiments is a rectangle over the U.S. The results of one annual as well as two-month simulations for the anomalous climate event of the U.S. drought of 1988, are validated against data analysis fields and diagnostics. The efficient regional down-scaling as well as the positive impact of fine regional resolution, are obtained. The SG-concept appeared to be a promising candidate for regional and subregional climate studies and applications.

  10. Infrared laser spectroscopy of the n-propyl and i-propyl radicals: Stretch-bend Fermi coupling in the alkyl CH stretch region

    Science.gov (United States)

    Franke, Peter R.; Tabor, Daniel P.; Moradi, Christopher P.; Douberly, Gary E.; Agarwal, Jay; Schaefer, Henry F.; Sibert, Edwin L.

    2016-12-01

    The n-propyl and i-propyl radicals were generated in the gas phase via pyrolysis of n-butyl nitrite [CH3(CH2)3ONO] and i-butyl nitrite [(CH3)2CHCH2ONO], respectively. Nascent radicals were promptly solvated by a beam of He nanodroplets, and the infrared spectra of the radicals were recorded in the CH stretching region. Several previously unreported bands are observed between 2800 and 3150 cm-1. The CH stretching modes observed above 3000 cm-1 are in excellent agreement with CCSD(T) anharmonic frequencies computed using second-order vibrational perturbation theory. However, between 2800 and 3000 cm-1, the spectra of n- and i-propyl radicals become congested and difficult to assign due to the presence of multiple anharmonic resonance polyads. To model the spectrally congested region, Fermi and Darling-Dennison resonances are treated explicitly using "dressed" Hamiltonians and CCSD(T) quartic force fields in the normal mode representation, and the agreement with experiment is less than satisfactory. Computations employing local mode effective Hamiltonians reveal the origin of the spectral congestion to be strong coupling between the high frequency CH stretching modes and the lower frequency CHn bending/scissoring motions. The most significant coupling is between stretches and bends localized on the same CH2/CH3 group. Spectral simulations using the local mode approach are in excellent agreement with experiment.

  11. Regional Climate Studies with Variable-Resolution Stretched-Grid GCMs

    Science.gov (United States)

    Fox-Rabinovitz, Michael; Einaudi, Franco (Technical Monitor)

    2001-01-01

    A variable resolution GCM using a global stretched grid with fine resolution over the area(s) of interest, is a viable new approach to regional and subregional climate studies and applications. It is an alternative to the widely used nested grid approach introduced a decade ago as a pioneering step in regional climate modeling. The first version of the SG-GCM based on the GEOS (Goddard Earth Observing System) GCM using a finite-difference approximation, has been developed and thoroughly tested during the last few years. Successful simulations have been performed with the SG-GCM for the anomalous regional climate events of the U.S. 1988 summer drought and 1993 summer flood. They have shown the practical feasibility of the SG-approach for regional climate modeling. The GEOS SG-DAS (Data Assimilation System) incorporating the SG-GCM has also been developed and tested. The assimilated regional fields and diagnostics are used for validating the SG-GCM regional simulations. Two new SG-GCMs are being developed. The first is the SG-version of the new NASANCAR FV-GCM (with the finite-volume (FV) dynamics), and the second is the SG-version of the new GCM with spectral-element dynamics. Both GCMs use the WAR CCM4 physics. Using these advanced numerics will provide increased computational efficiency for the new the SG-GCMs, and will allow us to employ more flexible stretching strategies beneficial for the efficient regional down-scaling. The major current developments are focused on: simulating the 1997-1999 (and beyond) ENSO cycle and related monsoonal circulations, with enhanced regional resolution; studying intraseasonal and interannual regional climate variability for the extended multiyear (AMIP-type) SG-GCM simulations; and studying the impact of ensemble integrations.

  12. Genomic Mapping of Human DNA provides Evidence of Difference in Stretch between AT and GC rich regions

    Science.gov (United States)

    Reifenberger, Jeffrey; Dorfman, Kevin; Cao, Han

    Human DNA is a not a polymer consisting of a uniform distribution of all 4 nucleic acids, but rather contains regions of high AT and high GC content. When confined, these regions could have different stretch due to the extra hydrogen bond present in the GC basepair. To measure this potential difference, human genomic DNA was nicked with NtBspQI, labeled with a cy3 like fluorophore at the nick site, stained with YOYO, loaded into a device containing an array of nanochannels, and imaged. Over 473,000 individual molecules of DNA, corresponding to roughly 30x coverage of a human genome, were collected and aligned to the human reference. Based on the known AT/GC content between aligned pairs of labels, the stretch was measured for regions of similar size but different AT/GC content. We found that regions of high GC content were consistently more stretched than regions of high AT content between pairs of labels varying in size between 2.5 kbp and 500 kbp. We measured that for every 1% increase in GC content there was roughly a 0.06% increase in stretch. While this effect is small, it is important to take into account differences in stretch between AT and GC rich regions to improve the sensitivity of detection of structural variations from genomic variations. NIH Grant: R01-HG006851.

  13. Regional Climate Simulation of the Anomalous Events of 1998 using a Stretched-Grid GCM with Multiple Areas of Interest

    Science.gov (United States)

    Fox-Rabinovitz, M. S.; Takacs, L. L.; Govindaraju, R. C.; Atlas, Robert (Technical Monitor)

    2002-01-01

    The GEOS (Goddard Earth Observing System) stretched-grid (SG) GCM developed and thoroughly tested over the last few years, is used for simulating the major anomalous regional climate events of 1998. The anomalous regional climate events are simulated simultaneously during the 13 months long (November-1997 - December-1998) SG-GCM simulation due to using the new SG-design with multiple (four) areas of interest. The following areas/regions of interest (one at each global quadrant) are implemented: U.S./Northern Mexico, the El-Nino/Brazil area, India-China, and Eastern Indian Ocean/Australia.

  14. Periostin shows increased evolutionary plasticity in its alternatively spliced region

    Directory of Open Access Journals (Sweden)

    Hoersch Sebastian

    2010-01-01

    Full Text Available Abstract Background Periostin (POSTN is a secreted extracellular matrix protein of poorly defined function that has been related to bone and heart development as well as to cancer. In human and mouse, it is known to undergo alternative splicing in its C-terminal region, which is devoid of known protein domains. Differential expression of periostin, sometimes of specific splicing isoforms, is observed in a broad range of human cancers, including breast, pancreatic, and colon cancer. Here, we combine genomic and transcriptomic sequence data from vertebrate organisms to study the evolution of periostin and particularly of its C-terminal region. Results We found that the C-terminal part of periostin is markedly more variable among vertebrates than the rest of periostin in terms of exon count, length, and splicing pattern, which we interpret as a consequence of neofunctionalization after the split between periostin and its paralog transforming growth factor, beta-induced (TGFBI. We also defined periostin's sequential 13-amino acid repeat units - well conserved in teleost fish, but more obscure in higher vertebrates - whose secondary structure is predicted to be consecutive beta strands. We suggest that these beta strands may mediate binding interactions with other proteins through an extended beta-zipper in a manner similar to the way repeat units in bacterial cell wall proteins have been reported to bind human fibronectin. Conclusions Our results, obtained with the help of the increasingly large collection of complete vertebrate genomes, document the evolutionary plasticity of periostin's C-terminal region, and for the first time suggest a basis for its functional role.

  15. Contaminants in tracked seabirds showing regional patterns of marine pollution.

    Science.gov (United States)

    Ito, Atsuo; Yamashita, Rei; Takada, Hideshige; Yamamoto, Takashi; Shiomi, Kozue; Zavalaga, Carlos; Abe, Tomoya; Watanabe, Shinichi; Yamamoto, Maki; Sato, Katsufumi; Kohno, Hiroyoshi; Yoda, Ken; Iida, Tomohiko; Watanuki, Yutaka

    2013-07-16

    Ocean-scale monitoring of pollution is challenging. Seabirds are useful indicators because they travel over a broad foraging range. Nevertheless, this coarse spatial resolution is not fine enough to discriminate pollution in a finer scale. Previous studies have demonstrated that pollution levels are higher in the Sea of Japan and South and East China Seas than the Northen Pacific Ocean. To test these findings in a wide-ranging animal, we tracked streaked shearwaters (Calonectris leucomelas) from four islands in Japan using global positioning system (GPS) and measured persistent organic pollutants (POPs) in the oil of their preen glands. The POPs did not change during 6 to 21 days when birds from Awashima were foraging only in the Sea of Japan, while it increased when they crossed to the Pacific through the Tsugaru Strait and foraged along the eastern coast of Hokkaido where industrial cities occur. These results indicate that POPs in the oil reflect relatively short-term exposure. Concentrations of POPs displayed greater variation among regions. Total polychlorinated biphenyls were highest in birds foraging in a small area of the semiclosed Seto Inland Sea surrounded by urbanized coast, p,p'-dichlorodiphenyltrichloroethane (DDT) was highest in birds foraging in the East China Sea, and total hexachlorocyclohexanes were highest in birds foraging in the Sea of Japan. All were lowest in birds foraging in the Pacific. This distribution of POPs concentration partly agrees with previous findings based on mussels, fish, and seawater and possibly reflects the mobility and emission sources of each type of POP. These results highlight the importance of information on the foraging area of highly mobile top predators to make them more effective monitors of regional marine pollution.

  16. Fourier Transform Absorption Spectroscopy of C_3 in the ν_3 Antisymmetric Stretch Mode Region

    Science.gov (United States)

    Vervloet, Michel; Martin-Drumel, Marie-Aline; Tokaryk, Dennis W.; Pirali, Olivier

    2017-06-01

    The C_3 molecule has been detected in a variety of astrophysical objects thanks to the well-known 4050 Å (A^1Π_u-X^1Σ ^+ _g) electronic transition as well as the two IR active modes of the electronic ground state: ν_2 (˜ 63.42 cm^{-1}) and ν_3 (˜ 2040.02 cm^{-1}). Previous laboratory data in the ν_3 region, obtained using diode laser spectroscopy and the photolysis of allene to produce C_3, permitted measurement of the fundamental (0,0,1)Σ-(0,0,0)Σ as well as the hot bands: (0,1,1)Π-(0,1,0)Π; (0,2,1)Σ-(0,2,0)Σ; (0,2,1)Δ-(0,2,0)Δ and provided insights on the anharmonicity of the (0,nν_2,1) vibrational pattern. We have recorded the absorption spectrum of C_3 in the 1800-2100 cm^{-1} region (at a resolution of 0.003 cm^{-1}) using the Bruker IFS 125 Fourier Transform spectrometer at the AILES beamline of Synchrotron SOLEIL. C_3 was produced in a DC discharge of methane heavily diluted in helium. The rovibrational temperature of C_3 produced in our discharge is noticeably higher than in Ref. [4], which allowed us to extend measurements to higher J values. More interestingly, we assigned new hot bands involving higher quanta of the ν_2 bending states: (0,nν_2,1) with n ranging from 0 to 5. Despite the absence of Q branches for these bands, which results in a possible ambiguous J-assignment of P and R lines, the large variety of data considered in this work, in addition to our experimental data and including observations of comet spectra, allows confident assignments. L. Gausset, G. Herzberg, A. Lagerqvist, B. Rosen, Astrophysical Journal, 45-81 (1965); T. F. Giesen et al., The Astrophysical Journal, 551, L181-L184 (2001) K. W. Hinkle, J. J. Keady, P. F. Bernath, Science, 241, 1319-1322 (1988) K. Kawaguchi et al., J. Chem. Phys., 91, 1953-1957 (1989)

  17. The stretching amplitude and thermal regime of the lithosphere in the nonvolcanic passive margin of Antarctica in the Mawson Sea region

    Science.gov (United States)

    Galushkin, Yu. I.; Leitchenkov, G. L.; Guseva, Yu. B.; Dubinin, E. P.

    2018-01-01

    The burial history and thermal evolution of the lithosphere within the passive nonvolcanic Antarctic margin in the region of the Mawson Sea are numerically reconstructed for the margin areas along the seismic profile 5909 with the use of the GALO basin modeling system. The amplitudes of the lithosphere stretching at the different stages of continental rifting which took place from 160 to 90 Ma ago are calculated from the geophysical estimates of the thickness of the consolidated crust and the tectonic analysis of the variations in the thickness of the sedimentary cover and sea depths during the evolution of the basin. It is hypothesized that the formation of the recent sedimentary section sequence in the studied region of the Antarctic margin began 140 Ma ago on a basement that was thinned by a factor of 1.6 to 4.5 during the first episode of margin stretching (160-140 Ma) under a fairly high heat flux. The reconstruction of the thermal regime of the lithosphere has shown that the mantle rocks could occur within the temperature interval of serpentinization and simultaneously within the time interval of lithospheric stretching (-160 fractures in these zones is less probable. However, serpentinization could take place in these areas as in the other margin segments at the stage of presedimentation ultra slow basement stretching.

  18. Vitronectin Binds to a Specific Stretch within the Head Region of Yersinia Adhesin A and Thereby Modulates Yersinia enterocolitica Host Interaction.

    Science.gov (United States)

    Mühlenkamp, Melanie C; Hallström, Teresia; Autenrieth, Ingo B; Bohn, Erwin; Linke, Dirk; Rinker, Janina; Riesbeck, Kristian; Singh, Birendra; Leo, Jack C; Hammerschmidt, Sven; Zipfel, Peter F; Schütz, Monika S

    2017-01-01

    Complement resistance is an important virulence trait of Yersinia enterocolitica (Ye). The predominant virulence factor expressed by Ye is Yersinia adhesin A (YadA), which enables bacterial attachment to host cells and extracellular matrix and additionally allows the acquisition of soluble serum factors. The serum glycoprotein vitronectin (Vn) acts as an inhibitory regulator of the terminal complement complex by inhibiting the lytic pore formation. Here, we show YadA-mediated direct interaction of Ye with Vn and investigated the role of this Vn binding during mouse infection in vivo. Using different Yersinia strains, we identified a short stretch in the YadA head domain of Ye O:9 E40, similar to the 'uptake region' of Y. pseudotuberculosis YPIII YadA, as crucial for efficient Vn binding. Using recombinant fragments of Vn, we found the C-terminal part of Vn, including heparin-binding domain 3, to be responsible for binding to YadA. Moreover, we found that Vn bound to the bacterial surface is still functionally active and thus inhibits C5b-9 formation. In a mouse infection model, we demonstrate that Vn reduces complement-mediated killing of Ye O:9 E40 and, thus, improved bacterial survival. Taken together, these findings show that YadA-mediated Vn binding influences Ye pathogenesis. © 2016 S. Karger AG, Basel.

  19. Vibrational Coupling Pathways in the CH Stretch Region of CH_3OH and CH_3OD as Revealed by IR and Ftmw-Ir Spectroscopies

    Science.gov (United States)

    Twagirayezu, Sylvestre; Wang, Xiaoliang; Perry, David S.; Neill, Justin L.; Muckle, Matt T.; Pate, Brooks H.; Xu, Li-Hong

    2011-06-01

    Infrared spectra of jet-cooled CH_3OD and CH_3OH in the CH stretch region are observed by coherence-converted population transfer Fourier transform microwave-infrared (CCPT-FTMW-IR) spectroscopy (E torsional species only) and by slit-jet single resonance spectroscopy (both A and E torsional species, CH_3OH only). Previously, we reported the analysis of ν_3 symmetric CH stretch region (2750-2900 Cm-1), and the present work extends the analysis to higher frequency (2900-3020 Cm-1). The overall observed spectra contain 17 interacting vibrational bands for CH_3OD and 28 for CH_3OH. The signs and magnitudes of the torsional tunneling splittings are deduced for three CH fundamentals (ν_3, ν_9, ν_2) of both molecules and are compared to a model calculation and to ab initio theory. The number and distribution of observed vibrational bands indicate that the CH stretch bright states couple first to doorway states that are binary combinations of bending modes. In the parts of the spectrum where doorway states are present, the observed density of coupled states is comparable to the total density of vibrational states in the molecule, but where there are no doorway states, only the CH stretch fundamentals are observed. A time-dependent interpretation of the present FTMW-IR spectra indicates a fast (˜ 200 fs) initial decay of the bright state followed by second, slower redistribution (˜ 1-3 ps). The qualitative agreement of the present data with the time-dependent experiments of Iwaki and Dlott provides further support for the similarity of the fastest vibrational relaxation processes in the liquid and gas phases. Twagirayezu, S.; Clasp, T. N.; Perry, D. S.; Neill, J. L.; Muckle, M. T.; Pate, B. H. J. Phys. Chem. A 2010, 114, 6818 Iwaki, L. K.; Dlott, D. D. J. Phys. Chem. A 2000, 104, 9101

  20. Effects of coronary artery bypass surgery on regions showing persistent defects in thallium myocardial images

    International Nuclear Information System (INIS)

    Konishi, Yutaka; Ban, Toshihiko; Okamoto, Yoshifumi

    1989-01-01

    The indications for revascularization surgery and its effects on myocardial regions showing persistent defects in thallium myocardial images are controversial. The effects of aortocoronary bypass surgery on myocardial perfusion and wall motion in the regions with persistent defects were evaluated in 47 patients with thallium-201 single photon emission computed tomography and left ventriculography. In areas showing persistent thallium defects preoperatively the rate of improvement of perfusion was only 24% by postoperative thallium imaging, and 57% by wall motion analysis. These results were significantly inferior to those of regions with transient defects, which were 84% and 82%, respectively. A persistent defect may not be a definitive marker of a non-viable scar, but the results of surgery on such regions were unsatisfactory. It is concluded, therefore, that revascuralization surgery in regions with persistent defects is not always recommended and that the indications for surgery should be individually determined with operative risk balanced against benefits. (author)

  1. Developing a Stretching Program.

    Science.gov (United States)

    Beaulieu, J E

    1981-11-01

    In brief: Although stretching exercises can prevent muscle injuries and enhance athletic performance, they can also cause injury. The author explains the four most common types of stretching exercises and explains why he considers static stretching the safest. He also sets up a stretching routine for runners. In setting up a safe stretching program, one should (1) precede stretching exercises with a mild warm-up; (2) use static stretching; (3) stretch before and after a workout; (4) begin with mild and proceed to moderate exercises; (5) alternate exercises for muscle groups; (6) stretch gently and slowly until tightness, not pain, is felt; and (7) hold the position for 30 to 60 seconds.

  2. Stretch Sensor Device

    DEFF Research Database (Denmark)

    2013-01-01

    The invention relates to a method for determining stretch values and movement of body parts, e.g. a foot, by analysing stretch data from a stretch sensor. By analysing data from the stretch sensor it is possible to determine stretch samples which are associated with particular motion phases...

  3. Temperature and Stretching Effects on Complementarity Determining Regions (CDRs Conformation and Stability of Nimotuzumab F(ab-Fragment

    Directory of Open Access Journals (Sweden)

    T.S. Humani

    2015-04-01

    Full Text Available Nimotuzumab is a humanized monoclonal antibody (mAb, a potential anticancer against epidermal growth factor receptor (EGFRoverexpressed by glioma, head and neck, lung, ovarium, and colon cancers. The combination of its use with both external and internal beam radiotherapies showed improvement of the therapeutic effect. However, the high molecular weight slows its uptake on tumor cells. In a recent development, nimotuzumab has been fragmented and then labeled using diagnostic and therapeutic radionuclides, such as gallium-68, yttrium-90, lutetium-177, and holmium-166. In that preparation, nimotuzumab is often conditioned in various environments with variations of pH, temperature and the presence of other compounds. In this research, molecular dynamics (MD simulation have been carried out to study the CDRs conformational change of nimotuzumab due to the effect of temperature, and also steered molecular dynamics (SMD simulation to study the stability of nimotuzumab domain as a result of external forces. The simulations were performed using the Not Just Another Molecular Dynamics (NAMD program package and the analysis was performed with the Visual Molecular Dynamics (VMD program package. Based on the stability analysis of each residue on the heavy chain, the active site (CDR3 region that is at residues numbered 98 (Tryptophan and 99 (Phenylalanine has the highest conformational changes. On the light chain, the change occurs at residues numbered 1 (Aspartat, 127 (Serin, and 186 (Tyrosine; and that none of that residues is part of active site or CDRs region of the light chain. The SMD simulation was carried out by fixing the N-terminal end of the heavy chain and applying external forces to the C-terminal end. The pulling was set at a constant velocity of 0.5 Å/ps. The force peak arising at the beginning of the unfolding process is 1226 pN. This force was allegedly caused by the rupture of hydrogen bonds between the heavy chain residue VAL211 (Valine

  4. Crustal Stretching Style and Lower Crust Flow of the South China Sea Northern Margin

    Science.gov (United States)

    Bai, Y.; Dong, D.; Runlin, D.

    2017-12-01

    There is a controversy about crustal stretching style of the South China Sea (SCS) northern margin mainly due to considerable uncertainty of stretching factor estimation, for example, as much as 40% of upper crust extension (Walsh et al., 1991) would be lost by seismic profiles due to poor resolution. To discover and understand crustal stretching style and lower crustal flow on the whole, we map the Moho and Conrad geometries based on gravity inversion constrained by deep seismic profiles, then according to the assumption of upper and lower crust initial thickness, upper and lower crust stretching factors are estimated. According to the comparison between upper and lower crust stretching factors, the SCS northern margin could be segmented into three parts, (1) sediment basins where upper crust is stretched more than lower crust, (2) COT regions where lower crust is stretched more than upper crust, (3) other regions where the two layers have similar stretching factors. Stretching factor map shows that lower crust flow happened in both of COT and sediment basin regions where upper crust decouples with lower crust due to high temperature. Pressure contrast by sediment loading in basins and erosion in sediment-source regions will lead to lower crust flow away from sediment sink to source. Decoupled and fractured upper crust is stretched further by sediment loading and the following compensation would result in relatively thick lower crust than upper crust. In COT regions with thin sediment coverage, low-viscosity lower crust is easier to thin in extensional environment, also the lower crust tends to flow away induced by magma upwelling. Therefore, continental crust on the margin is not stretching in a constant way but varies with the tectonic setting changes. This work is supported by National Natural Science Foundation of China (Grant No. 41506055, 41476042) and Fundamental Research Funds for the Central Universities China (No.17CX02003A).

  5. Atomic Stretch: Optimally bounded real-time stretching and beyond

    DEFF Research Database (Denmark)

    Jensen, Rasmus Ramsbøl; Nielsen, Jannik Boll

    2016-01-01

    Atomic Stretch is a plugin for your preferred Adobe video editing tool, allowing real-time smooth and optimally bounded retarget-ting from and to any aspect ratio. The plugin allows preserving of high interest pixels through a protected region, attention redirection through color-modification, co......Atomic Stretch is a plugin for your preferred Adobe video editing tool, allowing real-time smooth and optimally bounded retarget-ting from and to any aspect ratio. The plugin allows preserving of high interest pixels through a protected region, attention redirection through color...

  6. Youth at risk for obesity show greater activation of striatal and somatosensory regions to food.

    Science.gov (United States)

    Stice, Eric; Yokum, Sonja; Burger, Kyle S; Epstein, Leonard H; Small, Dana M

    2011-03-23

    Obese humans, compared with normal-weight humans, have less striatal D2 receptors and striatal response to food intake; weaker striatal response to food predicts weight gain for individuals at genetic risk for reduced dopamine (DA) signaling, consistent with the reward-deficit theory of obesity. Yet these may not be initial vulnerability factors, as overeating reduces D2 receptor density, D2 sensitivity, reward sensitivity, and striatal response to food. Obese humans also show greater striatal, amygdalar, orbitofrontal cortex, and somatosensory region response to food images than normal-weight humans do, which predicts weight gain for those not at genetic risk for compromised dopamine signaling, consonant with the reward-surfeit theory of obesity. However, after pairings of palatable food intake and predictive cues, DA signaling increases in response to the cues, implying that eating palatable food contributes to increased responsivity. Using fMRI, we tested whether normal-weight adolescents at high- versus low-risk for obesity showed aberrant activation of reward circuitry in response to receipt and anticipated receipt of palatable food and monetary reward. High-risk youth showed greater activation in the caudate, parietal operculum, and frontal operculum in response to food intake and in the caudate, putamen, insula, thalamus, and orbitofrontal cortex in response to monetary reward. No differences emerged in response to anticipated food or monetary reward. Data indicate that youth at risk for obesity show elevated reward circuitry responsivity in general, coupled with elevated somatosensory region responsivity to food, which may lead to overeating that produces blunted dopamine signaling and elevated responsivity to food cues.

  7. Hydraulic fracture during epithelial stretching.

    Science.gov (United States)

    Casares, Laura; Vincent, Romaric; Zalvidea, Dobryna; Campillo, Noelia; Navajas, Daniel; Arroyo, Marino; Trepat, Xavier

    2015-03-01

    The origin of fracture in epithelial cell sheets subject to stretch is commonly attributed to excess tension in the cells' cytoskeleton, in the plasma membrane, or in cell-cell contacts. Here, we demonstrate that for a variety of synthetic and physiological hydrogel substrates the formation of epithelial cracks is caused by tissue stretching independently of epithelial tension. We show that the origin of the cracks is hydraulic; they result from a transient pressure build-up in the substrate during stretch and compression manoeuvres. After pressure equilibration, cracks heal readily through actomyosin-dependent mechanisms. The observed phenomenology is captured by the theory of poroelasticity, which predicts the size and healing dynamics of epithelial cracks as a function of the stiffness, geometry and composition of the hydrogel substrate. Our findings demonstrate that epithelial integrity is determined in a tension-independent manner by the coupling between tissue stretching and matrix hydraulics.

  8. A COMPARISION BETWEEN CROSSBODY STRETCH VERSUS SLEEPER STRETCH IN PERIARTHRITIS OF SHOULDER

    Directory of Open Access Journals (Sweden)

    Shaik Raheem Saheb

    2015-12-01

    Full Text Available Background: Recently Cross body stretch and Sleeper stretch are used to improve internal rotation Range of motion in Shoulder Pathologies. It was proposed to study the effect of cross body stretch and sleeper stretch in subjects with periarthritis of shoulder. Methods: 60 subjects with a mean age of 53 years having clinical diagnosis of Periarthritis of shoulder and full filled the inclusive criteria are taken. After the initial measurements, the subjects are randomly assigned into 2 stretching groups. Group-A performed the Sleeper stretch. Group-B performed a Cross body stretch. Both Groups performed the Stretch in Duration of 6weeks – once daily for 5 repetitions holding each stretch for 30 seconds for 5 days a week. Along with this technique conventional physiotherapy like IFT, overhead pulleys, Pendula exercises, Wall climbing exercises, mariners wheel exercises are performed. After the treatment, subjects were evaluated for their pain profile using visual analogue scale, Goniometer for measuring Range of motion. Results: For within group comparison we used Paired t-test analysis, For Between group comparison we used Independent t-test for statistical analysis. At the end of 6 weeks It was found that subjects treated with cross-body stretch showed significant improvement in terms of VAS scores and Range of motion scores (P=0.000 and patients treated with Sleeper stretch showed significant improvement in terms of VAS scores and Range of motion scores (P=0.000. When compared between Groups the VAS and Range of motion scores showed a significant improvement in Cross body stretch Group than the Sleeper stretch Group (P=0.000. Conclusion: It was concluded that both stretching techniques were found improvement in Range of motion and VAS and Cross-body Stretch showed more Significant improvement than the sleeper Stretch after 6 weeks treatment.

  9. Stretching Safely and Effectively

    Science.gov (United States)

    ... of stretching before or after hitting the trail, ballet floor or soccer field. Before you plunge into ... ballistic stretching on strength and muscular fatigue of ballet dancers and resistance-trained women. Journal of Strength ...

  10. Anharmonic Bend-Stretch Coupling in Water

    NARCIS (Netherlands)

    Lindner, Jörg; Vöhringer, Peter; Pshenichnikov, Maxim S.; Cringus, Dan; Wiersma, Douwe A.; Corkum, Paul; Jonas, David M.; Miller, R.J. Dwayne.; Weiner, Andrew M.

    2006-01-01

    Following excitation of the H-O-H bending mode of water molecules in solution the stretching mode region is monitored over its entire width. The anharmonic coupling between the two modes results in a substantial change of the transient stretch absorption that decays with the bend depopulation time.

  11. Minority Enrollment Gains Show Region's Progress toward College Completion Goals. Fact Book Bulletin

    Science.gov (United States)

    Southern Regional Education Board (SREB), 2012

    2012-01-01

    Nationwide, from 2005 to 2010, 1.6 minority (non-white) students enrolled in college for every additional white student who enrolled. In the SREB (Southern Regional Education Board) region that meant 700,312 more minority college students and 411,915 more white college students. Increases in minority student enrollment accounted for almost…

  12. Idiopathic cases of male infertility from a region in India show low ...

    Indian Academy of Sciences (India)

    Unknown

    with poor morphology and motility) – were examined. An institutional ethical committee had approved analysis of genetic disorders in ..... Havighurst T and Grosch J 1999 Defining regions of the Y- chromosome responsible for male infertility and identi- fication of a fourth AZF region (AZFd) by Y-chromosome microdeletion ...

  13. New investigation of the ν3 C-H stretching region of 12CH4 through the analysis of high temperature infrared emission spectra.

    Science.gov (United States)

    Amyay, Badr; Gardez, Aline; Georges, Robert; Biennier, Ludovic; Vander Auwera, Jean; Richard, Cyril; Boudon, Vincent

    2018-04-07

    The ν 3 C-H stretching region of methane was reinvestigated in this work using high temperature (620-1715 K) emission spectra recorded in Rennes at Doppler limited resolution. This work follows our recent global analysis of the Dyad system Δn = ±1 (1000-1500 cm -1 ), with n being the polyad number [B. Amyay et al., J. Chem. Phys. 144, 24312 (2016)]. Thanks to the high temperature, new assignments of vibration-rotation methane line positions have been achieved successfully in the Pentad system and some associated hot bands (Δn = ±2) observed in the spectral region 2600-3300 cm -1 . In particular, rotational assignments in the cold band [Pentad-ground state (GS)] and in the first related hot band (Octad-Dyad) were extended up to J = 30 and 27, respectively. In addition, 1525 new transitions belonging to the Tetradecad-Pentad hot band system were assigned for the first time, up to J = 20. The effective global model used to deal with the new assignments was developed to the 6th order for the first three polyads (Monad, Dyad, and Pentad), and to the 5th order for both the Octad and the Tetradecad. 1306 effective parameters were fitted with a dimensionless standard deviation σ = 2.64. The root mean square deviations d RMS obtained are 4.18 × 10 -3 cm -1 for the Pentad-GS cold band, 2.48 × 10 -3 cm -1 for the Octad-Dyad, and 1.43 × 10 -3 cm -1 for the Tetradecad-Pentad hot bands.

  14. Regional Brain Activation During Meditation Shows Time and Practice Effects: An Exploratory FMRI Study†

    Science.gov (United States)

    Baron Short, E.; Kose, Samet; Mu, Qiwen; Borckardt, Jeffery; Newberg, Andrew; George, Mark S.; Kozel, F. Andrew

    2010-01-01

    Meditation involves attentional regulation and may lead to increased activity in brain regions associated with attention such as dorsal lateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC). Using functional magnetic resonance imaging, we examined whether DLPFC and ACC were activated during meditation. Subjects who meditate were recruited and scanned on a 3.0 Tesla scanner. Subjects meditated for four sessions of 12 min and performed four sessions of a 6 min control task. Individual and group t-maps were generated of overall meditation response versus control response and late meditation response versus early meditation response for each subject and time courses were plotted. For the overall group (n = 13), and using an overall brain analysis, there were no statistically significant regional activations of interest using conservative thresholds. A region of interest analysis of the entire group time courses of DLPFC and ACC were statistically more active throughout meditation in comparison to the control task. Moreover, dividing the cohort into short (n = 8) and long-term (n = 5) practitioners (>10 years) revealed that the time courses of long-term practitioners had significantly more consistent and sustained activation in the DLPFC and the ACC during meditation versus control in comparison to short-term practitioners. The regional brain activations in the more practised subjects may correlate with better sustained attention and attentional error monitoring. In summary, brain regions associated with attention vary over the time of a meditation session and may differ between long- and short-term meditation practitioners. PMID:18955268

  15. Regional Brain Activation during Meditation Shows Time and Practice Effects: An Exploratory FMRI Study

    Directory of Open Access Journals (Sweden)

    E. Baron Short

    2010-01-01

    Full Text Available Meditation involves attentional regulation and may lead to increased activity in brain regions associated with attention such as dorsal lateral prefrontal cortex (DLPFC and anterior cingulate cortex (ACC. Using functional magnetic resonance imaging, we examined whether DLPFC and ACC were activated during meditation. Subjects who meditate were recruited and scanned on a 3.0 Tesla scanner. Subjects meditated for four sessions of 12 min and performed four sessions of a 6 min control task. Individual and group t-maps were generated of overall meditation response versus control response and late meditation response versus early meditation response for each subject and time courses were plotted. For the overall group (n = 13, and using an overall brain analysis, there were no statistically significant regional activations of interest using conservative thresholds. A region of interest analysis of the entire group time courses of DLPFC and ACC were statistically more active throughout meditation in comparison to the control task. Moreover, dividing the cohort into short (n = 8 and long-term (n = 5 practitioners (>10 years revealed that the time courses of long-term practitioners had significantly more consistent and sustained activation in the DLPFC and the ACC during meditation versus control in comparison to short-term practitioners. The regional brain activations in the more practised subjects may correlate with better sustained attention and attentional error monitoring. In summary, brain regions associated with attention vary over the time of a meditation session and may differ between long- and short-term meditation practitioners.

  16. Stretched Wire Mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Bowden, Gordon; /SLAC

    2005-09-06

    Stretched wires are beginning to play an important role in the alignment of accelerators and synchrotron light sources. Stretched wires are proposed for the alignment of the 130 meter long LCLS undulator. Wire position technology has reached sub-micron resolution yet analyses of perturbations to wire straightness are hard to find. This paper considers possible deviations of stretched wire from the simple 2-dimensional catenary form.

  17. Wrinkling instability of an inhomogeneously stretched viscous sheet

    Science.gov (United States)

    Srinivasan, Siddarth; Wei, Zhiyan; Mahadevan, L.

    2017-07-01

    Motivated by the redrawing of hot glass into thin sheets, we investigate the shape and stability of a thin viscous sheet that is inhomogeneously stretched in an imposed nonuniform temperature field. We first determine the associated base flow by solving the long-time-scale stretching flow of a flat sheet as a function of two dimensionless parameters: the normalized stretching velocity α and a dimensionless width of the heating zone β . This allows us to determine the conditions for the onset of an out-of-plane wrinkling instability stated in terms of an eigenvalue problem for a linear partial differential equation governing the displacement of the midsurface of the sheet. We show that the sheet can become unstable in two regions that are upstream and downstream of the heating zone where the minimum in-plane stress is negative. This yields the shape and growth rates of the most unstable buckling mode in both regions for various values of the stretching velocity and heating zone width. A transition from stationary to oscillatory unstable modes is found in the upstream region with increasing β , while the downstream region is always stationary. We show that the wrinkling instability can be entirely suppressed when the surface tension is large enough relative to the magnitude of the in-plane stress. Finally, we present an operating diagram that indicates regions of the parameter space that result in a required outlet sheet thickness upon stretching while simultaneously minimizing or suppressing the out-of-plane buckling, a result that is relevant for the glass redraw method used to create ultrathin glass sheets.

  18. Coupled regional climate-ice-sheet simulation shows limited Greenland ice loss during the Eemian

    OpenAIRE

    Helsen, M. M.; van de Berg, W. J.; van de Wal, R. S. W.; van den Broeke, M. R.; Oerlemans, J.

    2013-01-01

    During the last interglacial period (Eemian, 130–115 kyr BP) eustatic global sea level likely peaked at > 6 m above the present-day level, but estimates of the contribution of the Greenland Ice Sheet vary widely. Here we use an asynchronously two-way-coupled regional climate–ice-sheet model, which includes physically realistic feedbacks between the changing ice sheet topography and climate forcing. Our simulation results in a contribution from the Greenland Ice Sheet to the ...

  19. Stretching: Does It Help?

    Science.gov (United States)

    Vardiman, Phillip; Carrand, David; Gallagher, Philip M.

    2010-01-01

    Stretching prior to activity is universally accepted as an important way to improve performance and help prevent injury. Likewise, limited flexibility has been shown to decrease functional ability and predispose a person to injuries. Although this is commonly accepted, appropriate stretching for children and adolescents involved with sports and…

  20. Dynamic stretching is effective as static stretching at increasing flexibility

    OpenAIRE

    Coons, John M.; Gould, Colleen E.; Kim, Jwa K.; Farley, Richard S.; Caputo, Jennifer L.

    2017-01-01

    This study examined the effect of dynamic and static (standard) stretching on hamstring flexibility. Twenty-five female volleyball players were randomly assigned to dynamic (n = 12) and standard (n = 13) stretching groups. The experimental group trained with repetitive dynamic stretching exercises, while the standard modality group trained with static stretching exercises. The stretching interventions were equivalent in the time at stretch and were performed three days a week for four weeks. ...

  1. Biaxial stretching of polyethylene, (2)

    International Nuclear Information System (INIS)

    Sakami, Hiroshi; Iida, Shozo

    1976-01-01

    The mechanism of oriented crystallization in mutually perpendicular direction to each other was investigated on the crosslinked linear polyethylene stretched successively and biaxially above melting point of raw material. To investigate the mechanism, the shrinkage stress, the degree of polarization and DSC of the film at the fixed length were measured on the crystallization process. The behavior observed on crystallization could be divided into that in the first period and that in the second period. The first period showed the domain of highly oriented crystallization of the crosslinked molecular chain, and in the second period the fold type crystals grew with highly oriented crystals in the first period as nuclear. Therefore, the formation of bi-component crystal structure is supposed for the crystallization. The biaxially oriented crystallization proceeded as follows: the uniaxial orientation to MD was observed in the first stretching in the initial stage, and then the further processing by the second stretching at a right angle caused the fold type crystallization of molecular chain oriented to TD. The film stretched fully and biaxially could be considered to have the oriented crystalline structure in which highly oriented fibril crystals and fold type crystals distribute at random. (auth.)

  2. Biocatalysis: Unmasked by stretching

    Science.gov (United States)

    Kharlampieva, Eugenia; Tsukruk, Vladimir V.

    2009-09-01

    The biocatalytic activity of enzyme-loaded responsive layer-by-layer films can be switched on and off by simple mechanical stretching. Soft materials could thus be used to trigger biochemical reactions under mechanical action, with potential therapeutic applications.

  3. Stretched alignment due to pairing correlation between the normal and abnormal parity orbits for the γ-soft nuclei in the light rare-earth region

    International Nuclear Information System (INIS)

    Ding, H.; Wu, L.

    1996-01-01

    For the γ-soft rotational motion, a two-parameter model is constructed considering the pair correlation between the normal and abnormal parity states based on the fermion dynamical symmetry model. The numerical calculation of this model shows that the data of ground bands of ten typical γ-soft rotational nuclei in the light rare-earth region are fitted in a very high quality. copyright 1996 The American Physical Society

  4. BSDB: the Biomolecule Stretching Database

    Science.gov (United States)

    Cieplak, Marek; Sikora, Mateusz; Sulkowska, Joanna I.; Witkowski, Bartlomiej

    2011-03-01

    Despite more than a decade of experiments on single biomolecule manipulation, mechanical properties of only several scores of proteins have been measured. A characteristic scale of the force of resistance to stretching, Fmax , has been found to range between ~ 10 and 480 pN. The Biomolecule Stretching Data Base (BSDB) described here provides information about expected values of Fmax for, currently, 17 134 proteins. The values and other characteristics of the unfolding proces, including the nature of identified mechanical clamps, are available at www://info.ifpan.edu.pl/BSDB/. They have been obtained through simulations within a structure-based model which correlates satisfactorily with the available experimental data on stretching. BSDB also lists experimental data and results of the existing all-atom simulations. The database offers a Protein-Data-Bank-wide guide to mechano-stability of proteins. Its description is provided by a forthcoming Nucleic Acids Research paper. Supported by EC FUNMOL project FP7-NMP-2007-SMALL-1, and European Regional Development Fund: Innovative Economy (POIG.01.01.02-00-008/08).

  5. Stretch due to Penile Prosthesis Reservoir Migration

    Directory of Open Access Journals (Sweden)

    E. Baten

    2016-03-01

    Full Text Available A 43-year old patient presented to the emergency department with stretch, due to impossible deflation of the penile prosthesis, 4 years after successful implant. A CT-scan showed migration of the reservoir to the left rectus abdominis muscle. Refilling of the reservoir was inhibited by muscular compression, causing stretch. Removal and replacement of the reservoir was performed, after which the prosthesis was well-functioning again. Migration of the penile prosthesis reservoir is extremely rare but can cause several complications, such as stretch.

  6. Brain Regions Showing White Matter Loss in Huntington's Disease Are Enriched for Synaptic and Metabolic Genes.

    Science.gov (United States)

    McColgan, Peter; Gregory, Sarah; Seunarine, Kiran K; Razi, Adeel; Papoutsi, Marina; Johnson, Eileanoir; Durr, Alexandra; Roos, Raymund A C; Leavitt, Blair R; Holmans, Peter; Scahill, Rachael I; Clark, Chris A; Rees, Geraint; Tabrizi, Sarah J

    2018-03-01

    The earliest white matter changes in Huntington's disease are seen before disease onset in the premanifest stage around the striatum, within the corpus callosum, and in posterior white matter tracts. While experimental evidence suggests that these changes may be related to abnormal gene transcription, we lack an understanding of the biological processes driving this regional vulnerability. Here, we investigate the relationship between regional transcription in the healthy brain, using the Allen Institute for Brain Science transcriptome atlas, and regional white matter connectivity loss at three time points over 24 months in subjects with premanifest Huntington's disease relative to control participants. The baseline cohort included 72 premanifest Huntington's disease participants and 85 healthy control participants. We show that loss of corticostriatal, interhemispheric, and intrahemispheric white matter connections at baseline and over 24 months in premanifest Huntington's disease is associated with gene expression profiles enriched for synaptic genes and metabolic genes. Corticostriatal gene expression profiles are predominately associated with motor, parietal, and occipital regions, while interhemispheric expression profiles are associated with frontotemporal regions. We also show that genes with known abnormal transcription in human Huntington's disease and animal models are overrepresented in synaptic gene expression profiles, but not in metabolic gene expression profiles. These findings suggest a dual mechanism of white matter vulnerability in Huntington's disease, in which abnormal transcription of synaptic genes and metabolic disturbance not related to transcription may drive white matter loss. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  7. Face-selective regions show invariance to linear, but not to non-linear, changes in facial images.

    Science.gov (United States)

    Baseler, Heidi A; Young, Andrew W; Jenkins, Rob; Mike Burton, A; Andrews, Timothy J

    2016-12-01

    Familiar face recognition is remarkably invariant across huge image differences, yet little is understood concerning how image-invariant recognition is achieved. To investigate the neural correlates of invariance, we localized the core face-responsive regions and then compared the pattern of fMR-adaptation to different stimulus transformations in each region to behavioural data demonstrating the impact of the same transformations on familiar face recognition. In Experiment 1, we compared linear transformations of size and aspect ratio to a non-linear transformation affecting only part of the face. We found that adaptation to facial identity in face-selective regions showed invariance to linear changes, but there was no invariance to non-linear changes. In Experiment 2, we measured the sensitivity to non-linear changes that fell within the normal range of variation across face images. We found no adaptation to facial identity for any of the non-linear changes in the image, including to faces that varied in different levels of caricature. These results show a compelling difference in the sensitivity to linear compared to non-linear image changes in face-selective regions of the human brain that is only partially consistent with their effect on behavioural judgements of identity. We conclude that while regions such as the FFA may well be involved in the recognition of face identity, they are more likely to contribute to some form of normalisation that underpins subsequent recognition than to form the neural substrate of recognition per se. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. SNPs in the FOXP3 gene region show no association with Juvenile Idiopathic Arthritis in a UK Caucasian population

    Science.gov (United States)

    Eastell, T.; Hinks, A.; Thomson, W.

    2007-01-01

    Objective A region on the short arm of the X-chromosome, Xp11, has previously been linked to childhood-onset polyarthritis. Mapping to the linked region is FOXP3, a transcription factor that regulates regulatory T cell (Treg) development and function. The objective of this study was to determine whether single nucleotide polymorphisms (SNPs) in the FOXP3 gene region contribute to JIA susceptibility. Method Nine FOXP3 SNPs were genotyped in 761 JIA cases and 402 controls using the Sequenom® MassARRAY® system. Association was measured using either χ2 or Fisher's exact test at the allelic and genotypic level. Furthermore, cases and controls were stratified by gender and association measured for each stratum. Results None of the SNPs showed an association with JIA. Similarly, the lack of association was also evident in both the female and male cohorts. Conclusion Although FOXP3 presents itself as a good candidate for contributing to JIA susceptibility, this study, which was powered to detect associations with genotypic relative risk >2 in the female cohort, has failed to find an association between SNPs in the FOXP3 gene region and JIA. PMID:17526924

  9. Stretching & Flexibility: An Interactive Encyclopedia of Stretching. [CD-ROM].

    Science.gov (United States)

    2002

    This CD-ROM offers 140 different stretches in full-motion video sequences. It focuses on the proper techniques for overall physical fitness, injury prevention and rehabilitation, and 23 different sports (e.g., golf, running, soccer, skiing, climbing, football, and baseball). Topics include stretching for sports; stretching awareness and education…

  10. Development of an aerosol-chemistry transport model coupled to non-hydrostatic icosahedral atmospheric model (NICAM) through applying a stretched grid system to regional simulations around Japan

    Science.gov (United States)

    Goto, D.; Nakajima, T.; Masaki, S.

    2014-12-01

    Air pollution has a great impact on both climate change and human health. One effective way to tackle with these issues is a use of atmospheric aerosol-chemistry models with high-resolution in a global scale. For this purpose, we have developed an aerosol-chemistry model based on a global cloud-resolving model (GCRM), Nonhydrostatic Icosahedral Atmospheric Model (NICAM; Tomita and Satoh, Fluid. Dyn. Res. 2004; Satoh et al., J. Comput. Phys. 2008, PEPS, 2014) under MEXT/RECCA/SALSA project. In the present study, we have simulated aerosols and tropospheric ozone over Japan by our aerosol-chemistry model "NICAM-Chem" with a stretched-grid system of approximately 10 km resolution, for saving the computer resources. The aerosol and chemistry modules are based on Spectral Radiation-Transport Model for Aerosol Species (SPRINTARS; Takemura et al., J. Geophys. Res., 2005) and Chemical AGCM for Study of Atmospheric Environment and Radiative Forcing (CHASER; Sudo et al., J. Geophys. Res., 2002). We found that our model can generally reproduce both aerosols and ozone, in terms of temporal variations (daily variations of aerosols and diurnal variations of ozone). Under MEXT/RECCA/SALSA project, we also have used these results obtained by NICAM-Chem for the assessment of their impact on human health.

  11. Stretching the Border

    DEFF Research Database (Denmark)

    Horstmann, Alexander

    2014-01-01

    In this paper, I hope to add a complementary perspective to James Scott’s recent work on avoidance strategies of subaltern mountain people by focusing on what I call the refugee public. The educated Karen elite uses the space of exile in the Thai borderland to reconstitute resources and to re-ent......-based organizations succeed to stretch the border by establishing a firm presence that is supported by the international humanitarian economy in the refugee camps in Northwestern Thailand....

  12. Bias of purine stretches in sequenced chromosomes

    DEFF Research Database (Denmark)

    Ussery, David; Soumpasis, Dikeos Mario; Brunak, Søren

    2002-01-01

    We examined more than 700 DNA sequences (full length chromosomes and plasmids) for stretches of purines (R) or pyrimidines (Y) and alternating YR stretches; such regions will likely adopt structures which are different from the canonical B-form. Since one turn of the DNA helix is roughly 10 bp, we...... measured the fraction of each genome which contains purine (or pyrimidine) tracts of lengths of 10 by or longer (hereafter referred to as 'purine tracts'), as well as stretches of alternating pyrimidines/purine ('pyr/pur tracts') of the same length. Using this criteria, a random sequence would be expected...... to contain 1.0% of purine tracts and also 1.0% of the alternating pyr/pur tracts. In the vast majority of cases, there are more purine tracts than would be expected from a random sequence, with an average of 3.5%, significantly larger than the expectation value. The fraction of the chromosomes containing pyr...

  13. Bias of purine stretches in sequenced chromosomes

    DEFF Research Database (Denmark)

    Ussery, David; Soumpasis, Dikeos Mario; Brunak, Søren

    2002-01-01

    We examined more than 700 DNA sequences (full length chromosomes and plasmids) for stretches of purines (R) or pyrimidines (Y) and alternating YR stretches; such regions will likely adopt structures which are different from the canonical B-form. Since one turn of the DNA helix is roughly 10 bp, we...... to contain 1.0% of purine tracts and also 1.0% of the alternating pyr/pur tracts. In the vast majority of cases, there are more purine tracts than would be expected from a random sequence, with an average of 3.5%, significantly larger than the expectation value. The fraction of the chromosomes containing pyr......, in eukaryotes there is an abundance of long stretches of purines or alternating purine/pyrimidine tracts, which cannot be explained in this way; these sequences are likely to play an important role in eukaryotic chromosome organisation....

  14. Map showing outcrop of the coal-bearing units and land use in the Gulf Coast region

    Science.gov (United States)

    Warwick, Peter D.; SanFilipo, John R.; Crowley, Sharon S.; Thomas, Roger E.; Freid, John; Tully, John K.

    1997-01-01

    This map is a preliminary compilation of the outcrop geology of the known coal-bearing units in the Gulf Coast Coal region. The map has been compiled for use in the National Coal Resource Assessment Project currently being conducted by the U.S. Geological Survey, and will be updated as the assessment progresses. The purpose of the map is to show the distribution of coal-bearing rocks in the Gulf Coastal Plain Region and to show stratigraphic correlations, transportation network, fossil-fuel burning power plants, and federally managed lands in the region. It is hoped that this map may aid coal exploration and development in the region. Geologic contacts were digitized from paper copies of the maps listed in the reference section below. The primary source of information was the 1:500,000-scale state geology map series, but larger scale maps were use to better define certain areas, notably the Jackson-Claiborne contact in western Kentucky and Tennessee for example (Olive, 1980). Contacts along state boundaries were modified to best-fit information available from the border areas. Note that coal distribution in the mapped units is not uniform. For example, the Jackson Group contains coal in Texas, but in Mississippi is not presently known to contain significant coal deposits. The unit is widespread and in part non-marine and thus of potential future interest. In contrast, the Jackson Group is not shown in Georgia where it is mostly marine and residuum (weathered material) at the surface. Tertiary age coal has also been noted in the Vicksburg Group (Oligocene) of Louisiana and Mississippi, but is not shown on this map. Contacts with mapped surficial units are not always shown. The locations of coal mine permit boundaries are based on information available at the time of publication and were obtained from the Division of Surface Mining and Reclamation, Railroad Commission of Texas, Austin, and the Injection and Mining Division, Department of Natural Resources, Baton

  15. Non-random expression of ribosomal DNA units in a grasshopper showing high intragenomic variation for the ITS2 region.

    Science.gov (United States)

    Ruiz-Estévez, M; Ruiz-Ruano, F J; Cabrero, J; Bakkali, M; Perfectti, F; López-León, M D; Camacho, J P M

    2015-06-01

    We analyse intragenomic variation of the ITS2 internal transcribed spacer of ribosomal DNA (rDNA) in the grasshopper Eyprepocnemis plorans, by means of tagged PCR 454 amplicon sequencing performed on both genomic DNA (gDNA) and RNA-derived complementary DNA (cDNA), using part of the ITS2 flanking coding regions (5.8S and 28S rDNA) as an internal control for sequencing errors. Six different ITS2 haplotypes (i.e. variants for at least one nucleotide in the complete ITS2 sequence) were found in a single population, one of them (Hap4) being specific to a supernumerary (B) chromosome. The analysis of both gDNA and cDNA from the same individuals provided an estimate of the expression efficiency of the different haplotypes. We found random expression (i.e. about similar recovery in gDNA and cDNA) for three haplotypes (Hap1, Hap2 and Hap5), but significant underexpression for three others (Hap3, Hap4 and Hap6). Hap4 was the most extremely underexpressed and, remarkably, it showed the lowest sequence conservation for the flanking 5.8-28S coding regions in the gDNA reads but the highest conservation (100%) in the cDNA ones, suggesting the preferential expression of mutation-free rDNA units carrying this ITS2 haplotype. These results indicate that the ITS2 region of rDNA is far from complete homogenization in this species, and that the different rDNA units are not expressed at random, with some of them being severely downregulated. © 2015 The Royal Entomological Society.

  16. Kontrola kvalitete stretch folije

    OpenAIRE

    Gržanić, Nino

    2016-01-01

    U završnom radu opisan je postupak ekstrudiranja i kontrole kvalitete stretch folije koji se koristi u firmi Bomark-Pak radi osiguravanja najbolje kvalitete. Kontrola kreče kod uvoza repromaterijala, nastavlja se kod izrade folije na stroju, te se glavni dio odvija nakon izrade gotovg proizvoda. U radu ćemo detaljno objasniti svaki pojedini korak, zašto se on vrši, te uz pomoć kojih mjernih instrumenata se izvršava.

  17. Global morphological analysis of marine viruses shows minimal regional variation and dominance of non-tailed viruses.

    Science.gov (United States)

    Brum, Jennifer R; Schenck, Ryan O; Sullivan, Matthew B

    2013-09-01

    Viruses influence oceanic ecosystems by causing mortality of microorganisms, altering nutrient and organic matter flux via lysis and auxiliary metabolic gene expression and changing the trajectory of microbial evolution through horizontal gene transfer. Limited host range and differing genetic potential of individual virus types mean that investigations into the types of viruses that exist in the ocean and their spatial distribution throughout the world's oceans are critical to understanding the global impacts of marine viruses. Here we evaluate viral morphological characteristics (morphotype, capsid diameter and tail length) using a quantitative transmission electron microscopy (qTEM) method across six of the world's oceans and seas sampled through the Tara Oceans Expedition. Extensive experimental validation of the qTEM method shows that neither sample preservation nor preparation significantly alters natural viral morphological characteristics. The global sampling analysis demonstrated that morphological characteristics did not vary consistently with depth (surface versus deep chlorophyll maximum waters) or oceanic region. Instead, temperature, salinity and oxygen concentration, but not chlorophyll a concentration, were more explanatory in evaluating differences in viral assemblage morphological characteristics. Surprisingly, given that the majority of cultivated bacterial viruses are tailed, non-tailed viruses appear to numerically dominate the upper oceans as they comprised 51-92% of the viral particles observed. Together, these results document global marine viral morphological characteristics, show that their minimal variability is more explained by environmental conditions than geography and suggest that non-tailed viruses might represent the most ecologically important targets for future research.

  18. Correlation between structure and conductivity in stretched Nafion

    Science.gov (United States)

    Allahyarov, Elshad; Taylor, Philip

    2008-03-01

    We have used coarse-grained simulation methods to investigate the effect of stretching-induced structure orientation on the proton conductivity of Nafion-like polyelectrolyte membranes. Recent experimental data on the morphology of ionomers describe Nafion as an aggregation of polymeric backbone chains forming elongated objects embedded in a continuous ionic medium. Uniaxial stretching of a recast Nafion film causes a preferential orientation of these objects in the direction of stretching. Our simulations of humid Nafion show that this has a strong effect on the proton conductivity, which is enhanced along the stretching direction, while the conductivity perpendicular to the stretched polymer backbone is strongly reduced. Stretching also causes the perfluorinated side chains to orient perpendicular to the stretching axis. The sulphonate multiplets shrink in diameter as the stretching is increased and show a spatially periodic ordering in their distribution. This in turn affects the distribution of contained water at low water contents. The water forms a continuous network with narrow bridges between small water clusters absorbed in head-group multiplets. We find the morphological changes in the stretched Nafion to be retained upon removal of the uniaxial stress.

  19. Transport, mixing and stretching in a chaotic Stokes flow: The two-roll mill

    International Nuclear Information System (INIS)

    Kaper, T.J.; Wiggins, S.

    1989-01-01

    We present the outline and preliminary results of an analytical and numerical study of transport, mixing, and stretching in a chaotic Stokes' flow in a two-roll mill apparatus. We use the theory of dynamical systems to describe the rich behavior and structure exhibited by these flows. The main features are the homoclinic tangle which functions as the backbone of the chaotic mixing region, the Smale horseshoe, and the island chains. We then use our detailed knowledge of these structures to develop a theory of transport and stretching of fluid in the chaotic regime. In particular, we show how a specific set of tools for adiabatic chaos- the adiabatic Melnikov function lobe area and flux computations and the adiabatic switching method is ideally suited to develop this theory of transport, mixing and stretching in time-dependent two-dimensional Stokes' flows. 19 refs., 8 figs

  20. Anisotropic dewetting on stretched elastomeric substrates.

    Science.gov (United States)

    Qiao, L; He, L H

    2008-08-01

    We study the instability of a very thin liquid film resting on a uniformly stretched soft elastomeric substrate driven by van der Waals forces. A linear stability analysis shows that the critical fluctuation wavelength in the tensile direction is larger than those in the other directions. The magnitudes of the critical wavelengths are adjustable in the sense that they depend on the principal stretch of the substrate. For example, when the principal stretch of the substrate varies from 1.0 (unstretched) to 3.0, the range of the critical wavelength in the tensile direction increases by 7.0% while that normal to the tensile direction decreases by 8.7%. Therefore, the phenomenon may find potential applications in creating tunable topographically patterned surfaces with nano- to microscale features.

  1. EFFECTIVENESS OF PNF STRETCHING VERSUS STATIC STRETCHING ON PAIN AND HAMSTRING FLEXIBILITY FOLLOWING MOIST HEAT IN INDIVIDUALS WITH KNEE OSTEOARTHRITIS

    Directory of Open Access Journals (Sweden)

    Meena .V

    2016-10-01

    Full Text Available Background: Osteoarthritis (OA is a degenerative joint disease and one of the major public health problem that causesfunctional impairment and reduced quality of life. To compare the effectiveness of PNF Hold relax stretching versus Static stretching on pain and flexibility of hamstring following moist heat in individuals with knee osteoarthritis. Hamstring tightness is the major problem in knee osteoarthritis individuals. Therefore the need of study is comparing the effectiveness of PNF Hold relax stretching versus static stretching on pain and flexibility of hamstrings following moist heat in knee osteoarthritis participants. Determining the effects of PNF Hold relax stretching versus Static stretching along with moist heat on pain and hamstring flexibility by VAS and Active knee extension range of motion in knee osteoarthritis individuals. Methods: 30 subjects with symptoms of knee osteoarthritis were randomly distributed into 2 groups 15 in each group. PNF Hold relax stretching along with moist heat is compared to Static stretching along with moist heat. Pain was measured by Visual Analogue Scale (VAS and hamstring flexibility by Active knee Extension Range of Motion (AKEROM by universal goniometer. Measurements are taken pre and post intervention. Results: The results indicated PNF Hold relax stretching along with moist heat showed a statistically significant improvement in pain (p<0.05 and improvement in hamstring flexibility (p<0.05 when compared to Static stretching along with moist heat. Conclusion: Subjects with PNF Hold relax stretching along with moist heat showed significant improvement in pain reduction and improving hamstring flexibility than Static stretching along with moist heat.

  2. Passive Stretch Versus Active Stretch on Intervertebral Movement in Non - Specific Neck Pain

    International Nuclear Information System (INIS)

    Abd El - Aziz, A.H.; Amin, D.I.; Moustafa, I.

    2016-01-01

    Neck pain is one of the most common and painful musculoskeletal conditions. Point prevalence ranges from 6% to 22% and up to 38% of the elderly population, while lifetime prevalence ranges from 14,2% to 71%. Up till now no randomized study showed the effect between controversy of active and passive stretch on intervertebral movement. The purpose: the current study was to investigate the effect of the passive and active stretch on intervertebral movement in non - specific neck pain. Material and methods: Forty five subjects from both sexes with age range between 18 and 30 years and assigned in three groups, group I (15) received active stretch, ultrasound and TENS. Group II (15) received passive stretch, ultrasound and TENS. Group III (15) received ultrasound and TENS. The radiological assessment was used to measure rotational and translational movement of intervertebral movement before and after treatment. Results: MANOVA test was used for radiological assessment before and after treatment there was significant increase in intervertebral movement in group I as p value =0.0001. Conclusion: active stretch had a effect in increasing the intervertebral movement compared to the passive stretch

  3. Contact angles on stretched solids

    Science.gov (United States)

    Mensink, Liz; Snoeijer, Jacco

    2017-11-01

    The surface energy of solid interfaces plays a central role in wetting, as they dictate the liquid contact angle. Yet, it has been challenging to measure the solid surface energies independently, without making use of Young's law. Here we present Molecular Dynamics (MD) simulations by which we measure the surface properties for all interfaces, including the solids. We observe change in contact angles upon stretching the solid substrates, showing that the surface energy is actually strain dependent. This is clear evidence of the so-called Shuttleworth effect, making it necessary to distinguish surface energy from surface tension. We discuss how this effect gives rise to a new class of elasto-capillary phenomena. ERC Consolidator Grant No. 616918.

  4. Electroforesis of Whey and Stretching Water Protein of Mozzarella Cheese Production from Factorial Experimental of Coagulation and Stretching Temperature

    Directory of Open Access Journals (Sweden)

    Purwadi Purwadi

    2012-02-01

    Full Text Available The use of lime juice as acidifier in the making of Mozzarella cheese was aimed to learn the protein profile of whey and stretching water produced with treatment of coagulation and stretching temperature. The treatment of coagulation temperature was G1 = 30oC, G2 = 35oC, G3 = 40oC, and G4 = 45oC, and the treatment of stretching temperature was M1 = 70oC, M2 = 75oC, M3 = 80oC, and M4 = 85oC. The research result showed that coagulation temperature of 30 and 35 oC gave the same protein profile of whey as well as coagulation temperature of 40 and 45oC, while coagulation temperature of 30 and 35oC with coagulation temperatur of 40 and 45oC gave different protein profile of whey. Different coagulation temperature gave different protein profile of whey and stretching water, while different stretching temperature gave the same protein profile of stretching water. Coagulation temperature of 30 and 35oC gave the same protein profile of stretching water as well as coagulation temperature of 40 and 45oC, while coagulation temperature of 30 and 35oC with temperature of 40 and 45oC gave different protein profile of stretching water. Keywords: protein profile, Mozzarella cheese, coagulation temperature, stretching temperature

  5. EFFICACY OF MODIFIED PROPRIOCEPTIVE NEUROMUSCULAR FACILITATION STRETCHING WITH CRYOTHERAPY OVER MANUAL PASSIVE STRETCHING WITH CRYOTHERAPY ON HAMSTRING FLEXIBILITY

    Directory of Open Access Journals (Sweden)

    Shamik Bhattacharjee

    2016-04-01

    Full Text Available Background: Healthy individuals, to ease and accomplish their activities of daily living they need flexible body without any tightness in the muscles, particularly those used for a definite function. Cooling soft tissues in a lengthened position after stretching has been shown to promote more lasting increases in soft tissue length and minimize post stretch muscle soreness. There are less documented studies which compared modified proprioceptive neuromuscular facilitation (PNF stretch over passive manual stretch with cold application commonly after the interventions. Methods: Thirty high school going healthy students were divided into two groups- Group I received Passive Manual stretching (n=15 and Group II received modified PNF stretching (n=15 and both groups received cold application after the interventions for 10 minutes commonly for 5 days. ROM was taken on day 1, day 5 and day 7. Results: After day 7, Group II with Modified PNF stretching along with cold application showed a significant increase in range of motion tested with active knee extension test (AKET. Conclusion: Modified PNF stretching is considered to be the effective intervention in increasing and maintaining ROM in AKET over passive manual stretching with cold applications commonly after the interventions.

  6. Effects on hamstring muscle extensibility, muscle activity, and balance of different stretching techniques.

    Science.gov (United States)

    Lim, Kyoung-Il; Nam, Hyung-Chun; Jung, Kyoung-Sim

    2014-02-01

    [Purpose] The purpose of this study was to investigate the effects of two different stretching techniques on range of motion (ROM), muscle activation, and balance. [Subjects] For the present study, 48 adults with hamstring muscle tightness were recruited and randomly divided into three groups: a static stretching group (n=16), a PNF stretching group (n=16), a control group (n=16). [Methods] Both of the stretching techniques were applied to the hamstring once. Active knee extension angle, muscle activation during maximum voluntary isometric contraction (MVC), and static balance were measured before and after the application of each stretching technique. [Results] Both the static stretching and the PNF stretching groups showed significant increases in knee extension angle compared to the control group. However, there were no significant differences in muscle activation or balance between the groups. [Conclusion] Static stretching and PNF stretching techniques improved ROM without decrease in muscle activation, but neither of them exerted statistically significant effects on balance.

  7. The effects of different volumes of dynamic stretching on 20-M ...

    African Journals Online (AJOL)

    ... each sprint) following different volumes of dynamic stretching (DSS1, DSS2 and DSS3). The results showed no significant difference for all parameters between all the all dynamic stretching volumes. Results show that any of the dynamic stretching volumes may be used as a warm up prior to the repeated sprints session.

  8. Stretch-minimising stream surfaces

    KAUST Repository

    Barton, Michael

    2015-05-01

    We study the problem of finding stretch-minimising stream surfaces in a divergence-free vector field. These surfaces are generated by motions of seed curves that propagate through the field in a stretch minimising manner, i.e., they move without stretching or shrinking, preserving the length of their arbitrary arc. In general fields, such curves may not exist. How-ever, the divergence-free constraint gives rise to these \\'stretch-free\\' curves that are locally arc-length preserving when infinitesimally propagated. Several families of stretch-free curves are identified and used as initial guesses for stream surface generation. These surfaces are subsequently globally optimised to obtain the best stretch-minimising stream surfaces in a given divergence-free vector field. Our algorithm was tested on benchmark datasets, proving its applicability to incompressible fluid flow simulations, where our stretch-minimising stream surfaces realistically reflect the flow of a flexible univariate object. © 2015 Elsevier Inc. All rights reserved.

  9. Acute Muscle Stretching and Shoulder Position Sense

    OpenAIRE

    Björklund, Martin; Djupsjöbacka, Mats; Crenshaw, Albert G

    2006-01-01

    Context: Stretching is common among athletes as a potential method for injury prevention. Stretching-induced changes in the muscle spindle properties are a suggested mechanism, which may imply reduced proprioception after stretching; however, little is known of this association.

  10. Stretch reflex regulation in healthy subjects and patients with spasticity

    DEFF Research Database (Denmark)

    Nielsen, Jens Bo; Petersen, Nicolas; Crone, Clarissa

    2005-01-01

    In recent years, part of the muscle resistance in spastic patients has been explained by changes in the elastic properties of muscles. However, the adaptive spinal mechanisms responsible for the exaggeration of stretch reflex activity also contribute to muscle stiffness. The available data suggest...... of the spastic symptoms. A recent finding also shows no sign of exaggerated stretch reflexes in muscles voluntarily activated by the spastic patient in general. This is easily explained by the control of stretch reflex activity in healthy subjects. In healthy subjects, the stretch reflex activity is increased...... movements, antagonist muscles should remain silent and maximally relaxed. This is ensured by increasing transmission in several spinal inhibitory pathways. In spastic patients, this control is inadequate, and therefore stretch reflexes in antagonist muscles are easily evoked at the beginning of voluntary...

  11. Linear and nonlinear buckling analysis of a locally stretched plate

    Energy Technology Data Exchange (ETDEWEB)

    Kilardj, Madina; Ikhenzzen, Ghania [University of Sciences and Technology Houari Boumediene (U.S.T.H.B), Bab Ezzouar, Algiers (Algeria); Merssager, Tanguy; Kanit, Toufik [Laboratoire de Mecanique de Lille Universite Lille 1, Cite ScientifiqueVilleneuve d' Ascq cedex (France)

    2016-08-15

    Uniformly stretched thin plates do not buckle unless they are in special boundary conditions. However, buckling commonly occurs around discontinuities, such as cracks, cuts, narrow slits, holes, and different openings, of such plates. This study aims to show that buckling can also occur in thin plates that contain no defect or singularity when the stretching is local. This specific stability problem is analyzed with the finite element method. A brief literature review on stretched plates is presented. Linear and nonlinear buckling stress analyses are conducted for a partially stretched rectangular plate, and various load cases are considered to investigate the influence of the partial loading expanse on the critical tensile buckling load. Results are summarized in iso-stress areas, tables and graphs. Local stretching on one end of the plate induces buckling in the thin plate even without geometrical imperfection.

  12. Randomized Controlled Trial Comparing Orthosis Augmented by Either Stretching or Stretching and Strengthening for Stage II Tibialis Posterior Tendon Dysfunction.

    Science.gov (United States)

    Houck, Jeff; Neville, Christopher; Tome, Josh; Flemister, Adolph

    2015-09-01

    The value of strengthening and stretching exercises combined with orthosis treatment in a home-based program has not been evaluated. The purpose of this study was to compare the effects of augmenting orthosis treatment with either stretching or a combination of stretching and strengthening in participants with stage II tibialis posterior tendon dysfunction (TPTD). Participants included 39 patients with stage II TPTD who were recruited from a medical center and then randomly assigned to a strengthening or stretching treatment group. Excluding 3 dropouts, there were 19 participants in the strengthening group and 17 in the stretching group. The stretching treatment consisted of a prefabricated orthosis used in conjunction with stretching exercises. The strengthening treatment consisted of a prefabricated orthosis used in conjunction with the stretching and strengthening exercises. The main outcome measures were self-report (ie, Foot Function Index and Short Musculoskeletal Function Assessment) and isometric deep posterior compartment strength. Two-way analysis of variance was used to test for differences between groups at 6 and 12 weeks after starting the exercise programs. Both groups significantly improved in pain and function over the 12-week trial period. The self-report measures showed minimal differences between the treatment groups. There were no differences in isometric deep posterior compartment strength. A moderate-intensity, home-based exercise program was minimally effective in augmenting orthosis wear alone in participants with stage II TPTD. Level I, prospective randomized study. © The Author(s) 2015.

  13. Soleus stretch reflex during cycling

    DEFF Research Database (Denmark)

    Grey, Michael James; Pierce, C. W.; Milner, T. E.

    2001-01-01

    the crank cycle, producing ankle dorsiflexion perturbations of similar trajectory. The stretch reflex was greatest during the power phase of the crank cycle and was decreased to the level of background EMG during recovery. Matched perturbations were induced under static conditions at the same crank angle...... active cycling as has been shown with the H-reflex. This lack of depression may reflect a decreased susceptibility of the stretch reflex to inhibition, possibly originating from presynaptic mechanisms....

  14. Vesper Sparrows and Western Meadowlarks Show a Mixed Response to Cattle Grazing in the Intermountain Region of British Columbia

    Directory of Open Access Journals (Sweden)

    Megan L. Harrison

    2010-06-01

    Full Text Available Livestock grazing in the shortgrass steppe of the Intermountain region of British Columbia is predicted to have significant effects on grassland habitats and their associated ground-nesting bird communities. We tested whether grazed and ungrazed sites could be discriminated on the basis of their vegetation communities, whether the abundance of two ground-nesting bird species, Vesper Sparrow (Pooecetes gramineus and Western Meadowlark (Sturnella neglecta, differed between grazed and ungrazed sites, and whether vegetation variables found to differ between grazed and ungrazed plots could be used to predict the abundance of the two bird species at a fine scale. Grazed sites were easily distinguishable from a site that had been ungrazed for >30 years based on the structure and composition of their vegetation communities. However, more detailed grazing categories could not be distinguished on the basis of vegetation characteristics. Despite the existence of grazing effects on vegetation structure and composition, we found no consistent differences in abundance of Vesper Sparrows and Western Meadowlarks between the grazed and ungrazed sites. However, there was weak evidence that the abundance of both species was higher at fine-scale plots (100 m radius point count station with less bare ground and taller vegetation. Bare ground cover was lower on grazed plots, but vegetation was taller on ungrazed plots. Combined, our results suggest that low intensity grazing leads to grassland habitat change with both negative and positive effects on Vesper Sparrows and Western Meadowlarks, resulting in no net change in their broad-scale abundance.

  15. The effectiveness of manual stretching in the treatment of plantar heel pain: a systematic review

    Directory of Open Access Journals (Sweden)

    Parish Ben

    2011-06-01

    Full Text Available Abstract Background Plantar heel pain is a commonly occurring foot complaint. Stretching is frequently utilised as a treatment, yet a systematic review focusing only on its effectiveness has not been published. This review aimed to assess the effectiveness of stretching on pain and function in people with plantar heel pain. Methods Medline, EMBASE, CINAHL, AMED, and The Cochrane Library were searched from inception to July 2010. Studies fulfilling the inclusion criteria were independently assessed, and their quality evaluated using the modified PEDro scale. Results Six studies including 365 symptomatic participants were included. Two compared stretching with a control, one study compared stretching to an alternative intervention, one study compared stretching to both alternative and control interventions, and two compared different stretching techniques and durations. Quality rating on the modified Pedro scale varied from two to eight out of a maximum of ten points. The methodologies and interventions varied significantly between studies, making meta-analysis inappropriate. Most participants improved over the course of the studies, but when stretching was compared to alternative or control interventions, the changes only reached statistical significance in one study that used a combination of calf muscle stretches and plantar fascia stretches in their stretching programme. Another study comparing different stretching techniques, showed a statistically significant reduction in some aspects of pain in favour of plantar fascia stretching over calf stretches in the short term. Conclusions There were too few studies to assess whether stretching is effective compared to control or other interventions, for either pain or function. However, there is some evidence that plantar fascia stretching may be more effective than Achilles tendon stretching alone in the short-term. Appropriately powered randomised controlled trials, utilizing validated outcome

  16. Relationship Between Stretch Duration And Shoulder Musculature ...

    African Journals Online (AJOL)

    To date, studies focussing on the effect of stretching on flexibility have focused almost solely on the effect of chronic stretching rather than the effects of acute stretching performed immediately prior to physical activity. The effects of different static stretches were assessed on passive shoulder range of motion (ROM).

  17. COMPARISON OF EFFECTIVENESS OF ISOMETRIC EXERCISES WITH AND WITHOUT STRETCHING EXERCISES IN NON SPECIFIC CERVICAL PAIN

    Directory of Open Access Journals (Sweden)

    Warda Hassan

    2016-06-01

    Full Text Available Background: Cervical pain is a common condition and almost two thirds of population suffers with this condition. Cervical region is the commonest region for non-traumatic neck pain. Neck pain generates many muscular disturbances in the neck region and may result in tightness of muscles of cervical region. Stretching is considered as an effective mean of treating cervical pain. Isometric exercise is used to enhance the performance of muscles because it provides strength required to perform dynamic exercise. Both of the regimens either separately or combined are used in clinical settings to treat nonspecific cervical pain. This study aims to compare the results of cervical isometrics with and without stretching exercises in reducing non-specific cervical pain Methods: A randomized controlled trial research was performed at physiotherapy department of Mayo Hospital Lahore, Pakistan. A convenience sample of 40 participants was divided into two groups. The cervical isometric exercise was applied to group A and stretching plus isometric exercise to group B for 3 weeks. Nonspecific neck pain was analyzed by using visual analogue scale and goniometry for pre and post treatment assessment. Results: Isometric exercises play an effective role in relieving pain (p value is 0.03 and minimizing inability of the body to perform functional activities (p value is 0.004 in contrast to the patients of group A. Isometric exercises were applied to the patients of group A (Level of pain: pain value is 0.172 and (physical inability to perform functional activities has P value 0.201. Conclusion: The result showed that the patients with the complain of non-specific neck discomfort who were treated by cervical isometric alone, showed less improvement in pain relief in contrast to the patients who were treated by the cervical isometric long with stretching.

  18. STRETCH FABRICS IN LEATHER MANUFACTURING: PERFORMANCE PROPERTIES OF STRECH LEATHERS

    Directory of Open Access Journals (Sweden)

    ORK Nilay

    2016-05-01

    Full Text Available Product variability of manufactured leather goods such as garment leathers could be closely related to the wear comfort because each material forming the garments are affected the comfort properties of the products. Considering the significant demand to elastic woven stretch fabrics and the advantages provided to leather goods like allowing easy body movements, well-fitting and keeping the shape make the use of stretch fabrics focus in interest. In this study, the performance properties of stretch leathers, leathers and spandex fabrics were presented and the differences between the characteristic properties of the leathers were described. For this purpose, physical characteristics of leathers were investigated in terms of thickness, weight, drape ability, stiffness, bending stiffness, air and water vapor permeability. The drape ability, stiffness and bending stiffness properties were significantly affected by the stretch fabrics laminated on the suede side of the leathers. The drape ability, stiffness and bending values were increased due to the implementation of stretch fabrics. There was no significant difference between the air permeability values of the leathers prior and after the implementation of stretch fabrics in contrast to water vapor permeability. The results of this study showed that the aesthetic behavior of clothing materials such as drape and stiffness properties as well as water vapor permeability was mainly affected from the implementation of the stretch fabrics.

  19. Acute Effects of Dynamic Stretching on Muscle Flexibility and Performance: An Analysis of the Current Literature.

    Science.gov (United States)

    Opplert, Jules; Babault, Nicolas

    2018-02-01

    Stretching has long been used in many physical activities to increase range of motion (ROM) around a joint. Stretching also has other acute effects on the neuromuscular system. For instance, significant reductions in maximal voluntary strength, muscle power or evoked contractile properties have been recorded immediately after a single bout of static stretching, raising interest in other stretching modalities. Thus, the effects of dynamic stretching on subsequent muscular performance have been questioned. This review aimed to investigate performance and physiological alterations following dynamic stretching. There is a substantial amount of evidence pointing out the positive effects on ROM and subsequent performance (force, power, sprint and jump). The larger ROM would be mainly attributable to reduced stiffness of the muscle-tendon unit, while the improved muscular performance to temperature and potentiation-related mechanisms caused by the voluntary contraction associated with dynamic stretching. Therefore, if the goal of a warm-up is to increase joint ROM and to enhance muscle force and/or power, dynamic stretching seems to be a suitable alternative to static stretching. Nevertheless, numerous studies reporting no alteration or even performance impairment have highlighted possible mitigating factors (such as stretch duration, amplitude or velocity). Accordingly, ballistic stretching, a form of dynamic stretching with greater velocities, would be less beneficial than controlled dynamic stretching. Notwithstanding, the literature shows that inconsistent description of stretch procedures has been an important deterrent to reaching a clear consensus. In this review, we highlight the need for future studies reporting homogeneous, clearly described stretching protocols, and propose a clarified stretching terminology and methodology.

  20. Acute effect of constant torque and angle stretching on range of motion, muscle passive properties, and stretch discomfort perception.

    Science.gov (United States)

    Cabido, Christian E T; Bergamini, Juliana C; Andrade, André G P; Lima, Fernando V; Menzel, Hans J; Chagas, Mauro H

    2014-04-01

    The aim of the present study was to compare the acute effects of constant torque (CT) and constant angle (CA) stretching exercises on the maximum range of motion (ROMmax), passive stiffness (PS), and ROM corresponding to the first sensation of tightness in the posterior thigh (FSTROM). Twenty-three sedentary men (age, 19-33 years) went through 1 familiarization session and afterward proceeded randomly to both CA and CT treatment stretching conditions, on separate days. An isokinetic dynamometer was used to analyze hamstring muscles during passive knee extension. The subjects performed 4 stretches of 30 seconds each with a 15-second interval between them. In the CA stretching, the subject reached a certain ROM (95% of ROMmax), and the angle was kept constant. However, in the CT stretching exercise, the volunteer reached a certain resistance torque (corresponding to 95% of ROMmax) and it was kept constant. The results showed an increase in ROMmax for both CA and CT (p stretch may be explained by greater changes in the biomechanical properties of the muscle-tendon unit and stretch tolerance, as indicated by the results of PS and FSTROM.

  1. Acute effects of unilateral static stretching on handgrip strength of the stretched and non-stretched limb.

    Science.gov (United States)

    Jelmini, Jacob D; Cornwell, Andrew; Khodiguian, Nazareth; Thayer, Jennifer; Araujo, And John

    2018-02-16

    To determine the effects of an acute bout of unilateral static stretching on handgrip strength of both the stretched and non-stretched limb. It was reasoned that if the non-stretched limb experienced a decrease in force output, further evidence for a neural mechanism to explain a post-stretch force reduction would be obtained as no mechanical adaptation would have occurred. Thirty participants performed maximum voluntary unilateral handgrip contractions of both limbs before and after stretching the finger flexors of the strength-dominant side only. Each trial was assessed for peak force, muscle activity (iEMG), and rate of force generation. Following the stretching bout, peak force and iEMG decreased by 4.4% (p = 0.001) and 6.4% (p = 0.000) respectively in the stretched limb only. However, rate of force generation was significantly impaired in both the stretched (- 17.3%; p = 0.000) and non-stretched limbs (- 10.8%; p = 0.003) 1 min post-stretch, and remained similarly depressed for both limbs 15 min later. Acute stretching negatively impacts rate of force generation more than peak force. Moreover, a reduced rate of force generation from the non-stretched limb indicates the presence of a cross-over inhibitory effect through the nervous system, which provides additional evidence for a neural mechanism.

  2. Soleus stretch reflex during cycling

    DEFF Research Database (Denmark)

    Grey, Michael James; Pierce, C. W.; Milner, T. E.

    2001-01-01

    The modulation and strength of the human soleus short latency stretch reflex was investigated by mechanically perturbing the ankle during an unconstrained pedaling task. Eight subjects pedaled at 60 rpm against a preload of 10 Nm. A torque pulse was applied to the crank at various positions durin...

  3. On the generalised stretch function

    Czech Academy of Sciences Publication Activity Database

    Kharlamov, Alexander A.; Filip, Petr

    2012-01-01

    Roč. 21, č. 4 (2012), s. 272-278 ISSN 1022-1344 R&D Projects: GA ČR GA103/09/2066 Institutional research plan: CEZ:AV0Z20600510 Keywords : molecular length * recurrence equations * rubber * strain * stretch functions Subject RIV: BK - Fluid Dynamics Impact factor: 1.606, year: 2012

  4. Optical tweezers stretching of chromatin

    NARCIS (Netherlands)

    Pope, L.H.; Bennink, Martin L.; Greve, Jan

    2003-01-01

    Recently significant success has emerged from exciting research involving chromatin stretching using optical tweezers. These experiments, in which a single chromatin fibre is attached by one end to a micron-sized bead held in an optical trap and to a solid surface or second bead via the other end,

  5. Transient filament stretching rheometer II

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Rasmussen, Henrik K.; Hassager, Ole

    1997-01-01

    The Lagrangian sspecification is used to simulate the transient stretching filament rheometer. Simulations are performed for dilute PIB-solutions modeled as a four mode Oldroyd-B fluid and a semidilute PIB-solution modeled as a non-linear single integral equation. The simulations are compared...

  6. Magnitude-dependent proliferation and contractility modulation of human bladder smooth muscle cells under physiological stretch.

    Science.gov (United States)

    Luo, De-Yi; Wazir, Romel; Du, Caigan; Tian, Ye; Yue, Xuan; Wei, Tang-Qiang; Wang, Kun-Jie

    2015-11-01

    The purpose of this study was to describe and test a kind of stretch pattern which is based on modified BOSE BioDynamic system to produce optimum physiological stretch during bladder cycle. Moreover, we aimed to emphasize the effects of physiological stretch's amplitude upon proliferation and contractility of human bladder smooth muscle cells (HBSMCs). HBSMCs were seeded onto silicone membrane and subjected to stretch simulating bladder cycle at the range of stretches and time according to customized software on modified BOSE BioDynamic bioreactor. Morphological changes were assessed using immunofluorescence and confocal laser scanning microscope. Cell proliferation and cell viability were determined by BrdU incorporation assay and Cell Counting Kit-8, respectively. Contractility of the cells was determined using collagen gel contraction assay. RT-PCR was used to assess phenotypic and contractility markers. HBSMCs were found to show morphologically spindle-shaped and orientation at various elongations in the modified bioreactor. Stretch-induced proliferation and viability depended on the magnitude of stretch, and stretches also regulate contractility and contraction markers in a magnitude-dependent manner. We described and tested a kind of stretch pattern which delivers physiological stretch implemented during bladder cycle. The findings also showed that mechanical stretch can promote magnitude-dependent morphological, proliferative and contractile modulation of HBSMCs in vitro.

  7. A comparison of assisted and unassisted proprioceptive neuromuscular facilitation techniques and static stretching.

    Science.gov (United States)

    Maddigan, Meaghan E; Peach, Ashley A; Behm, David G

    2012-05-01

    A comparison of assisted and unassisted proprioceptive neuromuscular facilitation techniques and static stretching. J Strength Cond Res 26(5): 1238-1244, 2012-Proprioceptive neuromuscular facilitation (PNF) stretching often requires a partner. Straps are available allowing an individual to perform PNF stretching alone. It is not known if a strap provides similar improvements in the range of motion (ROM) as partner-assisted PNF or static stretching. The purpose of this study was to compare assisted and unassisted (with a strap) PNF stretching and static stretching. Hip joint ROM, reaction time (RT), and movement time (MT) were measured prestretching and poststretching. Thirteen recreationally active adults participated in this study. The participants were subjected to 5 different stretch interventions in a random order on separate days. Stretch conditions included unassisted PNF stretching using (a) isometric, (b) concentric, and (c) eccentric contractions with a stretch strap, (d) partner-assisted isometric PNF, and (e) static stretching. The RT, MT, dynamic, active, passive hip flexion angle, and angular velocity with dynamic hip flexion were measured before and after the intervention. The ROM improved (p < 0.05) 2.6, 2.7, and 5.4%, respectively, with dynamic, active static, and passive static ROM, but there was no significant difference between the stretching protocols. There was a main effect for time (p < 0.05) with all stretching conditions negatively impacting dynamic angular velocity (9.2%). Although there was no significant effect on RT, MT showed a negative main effect for time (p < 0.05) slowing 3.4%. In conclusion, it was found that all 3 forms of active stretching provided similar improvements in the ROM and poststretching performance decrements in MT and angular velocity. Thus, individuals can implement PNF stretching techniques with a partner or alone with a strap to improve ROM, but athletes should not use these techniques before important

  8. A Novel Non-Planar Transverse Stretching Process for Micro-Porous PTFE Membranes and Resulting Characteristics

    KAUST Repository

    Chang, Y.-H.

    2018-02-26

    Polytetrafluoroethylene (PTFE) micro-porous membranes were prepared from PTFE fine powder through extruding, rolling, and uniaxial longitudinally stretching. In contrast to conventional planar transverse stretching, a novel 3D mold design of non-planar transverse stretching process was employed in this study to produce micro-porous structure. The morphology, membrane thickness, mean pore size, and porosity of the PTFE membrane were investigated. The results show that the non-planar transverse stretched membranes exhibit more uniform average pore diameter with thinner membrane thickness. Morphological changes induced by planar and non-planar transverse stretching for pore characteristics were investigated. The stretching conditions, stretching temperature and rate, affect the stretched membrane. Increasing temperature facilitated the uniformity of pore size and uniformity of membrane thickness. Moreover, increase in stretching rate resulted in finer pore size and thinner membrane.

  9. Cyclic stretch-induced stress fiber dynamics - Dependence on strain rate, Rho-kinase and MLCK

    International Nuclear Information System (INIS)

    Lee, Chin-Fu; Haase, Candice; Deguchi, Shinji; Kaunas, Roland

    2010-01-01

    Research highlights: → Cyclic stretch induces stress fiber disassembly, reassembly and fusion perpendicular to the direction of stretch. → Stress fiber disassembly and reorientation were not induced at low stretch frequency. → Stretch caused actin fiber formation parallel to stretch in distinct locations in cells treated with Rho-kinase and MLCK inhibitors. -- Abstract: Stress fiber realignment is an important adaptive response to cyclic stretch for nonmuscle cells, but the mechanism by which such reorganization occurs is not known. By analyzing stress fiber dynamics using live cell microscopy, we revealed that stress fiber reorientation perpendicular to the direction of cyclic uniaxial stretching at 1 Hz did not involve disassembly of the stress fiber distal ends located at focal adhesion sites. Instead, these distal ends were often used to assemble new stress fibers oriented progressively further away from the direction of stretch. Stress fiber disassembly and reorientation were not induced when the frequency of stretch was decreased to 0.01 Hz, however. Treatment with the Rho-kinase inhibitor (Y27632) reduced stress fibers to thin fibers located in the cell periphery which bundled together to form thick fibers oriented parallel to the direction of stretching at 1 Hz. In contrast, these thin fibers remained diffuse in cells subjected to stretch at 0.01 Hz. Cyclic stretch at 1 Hz also induced actin fiber formation parallel to the direction of stretch in cells treated with the myosin light chain kinase (MLCK) inhibitor ML-7, but these fibers were located centrally rather than peripherally. These results shed new light on the mechanism by which stress fibers reorient in response to cyclic stretch in different regions of the actin cytoskeleton.

  10. EFFECT OF STATIC STRETCHING ON STRENGTH OF HAMSTRING MUSCLE

    Directory of Open Access Journals (Sweden)

    Shweta P Pachpute

    2016-04-01

    Full Text Available Background: Flexibility is an indisputable component of fitness defined as the ability to move a single joint or series of joints through an unrestricted pain free range of motion. Static stretching consists of stretching a muscle or group of muscle to its farthest point and then maintaining or holding that position. The literature supports that muscles are capable of exerting their greatest strength when they are fully lengthen. Hence this study was conducted to find the effect of static stretching on hamstring muscle. Methods: The study was experimental study design. 40 samples were selected by purposive sampling method. Flexibility of the hamstring muscle unilaterally right side (arbitrarily chosen was measured by active knee extension test of all the subjects who met the inclusion criteria of the study. After measuring the flexibility of hamstring muscle, strength was measured by 1RM for the same side (right hamstring muscle. Static Stretching Protocol was given for 5 days per week for 6 weeks to all the participants. After the 6 weeks of training, knee extension deficiency and 1RM was documented. Result: Statistical analysis using Paired t-test was done. The t-test showed that there was significant effect of static stretching on 1RM of hamstring muscle (p<0.05 & active knee extension test (p=0.000. Conclusion: Static stretching showed significant change in pre and post 1RM of hamstring muscle and active knee extension test. There was significant improvement of hamstring muscles flexibility and strength after giving static stretching in female population. So it is possible that females who are unable to participate in traditional strength training activities may be able to experience gains through static stretching.

  11. Effect of acute stretch injury on action potential and network activity of rat neocortical neurons in culture.

    Science.gov (United States)

    Magou, George C; Pfister, Bryan J; Berlin, Joshua R

    2015-10-22

    The basis for acute seizures following traumatic brain injury (TBI) remains unclear. Animal models of TBI have revealed acute hyperexcitablility in cortical neurons that could underlie seizure activity, but studying initiating events causing hyperexcitability is difficult in these models. In vitro models of stretch injury with cultured cortical neurons, a surrogate for TBI, allow facile investigation of cellular changes after injury but they have only demonstrated post-injury hypoexcitability. The goal of this study was to determine if neuronal hyperexcitability could be triggered by in vitro stretch injury. Controlled uniaxial stretch injury was delivered to a spatially delimited region of a spontaneously active network of cultured rat cortical neurons, yielding a region of stretch-injured neurons and adjacent regions of non-stretched neurons that did not directly experience stretch injury. Spontaneous electrical activity was measured in non-stretched and stretch-injured neurons, and in control neuronal networks not subjected to stretch injury. Non-stretched neurons in stretch-injured cultures displayed a three-fold increase in action potential firing rate and bursting activity 30-60 min post-injury. Stretch-injured neurons, however, displayed dramatically lower rates of action potential firing and bursting. These results demonstrate that acute hyperexcitability can be observed in non-stretched neurons located in regions adjacent to the site of stretch injury, consistent with reports that seizure activity can arise from regions surrounding the site of localized brain injury. Thus, this in vitro procedure for localized neuronal stretch injury may provide a model to study the earliest cellular changes in neuronal function associated with acute post-traumatic seizures. Copyright © 2015. Published by Elsevier B.V.

  12. Infrared spectroscopy and Density Functional Theory of crystalline β-2,4,6,8,10,12-hexanitrohexaaziosowurtzitane (β CL-20) in the region of its C-H stretching vibrations.

    Science.gov (United States)

    Behler, K D; Pesce-Rodriguez, R; Cabalo, J; Sausa, R

    2013-10-01

    Molecular vibrational spectroscopy provides a useful tool for material characterization and model verification. We examine the CH stretching fundamental and overtones of energetic material β-2,4,6,8,10,12-hexanitrohexaaziosowurtzitane (β-CL-20) by Raman spectroscopy, Fourier Transform Infrared Spectroscopy, and Laser Photoacoustic Overtone Spectroscopy, and utilize Density Functional Theory to calculate the C-H bond energy of β-CL-20 in a crystal. The spectra reveal four intense and distinct features, whose analysis yields C-H stretching fundamental frequencies and anharmonicity values that range from 3137 to 3170 cm(-1) and 53.8 to 58.8 cm(-1), respectively. From these data, we estimate an average value of 42,700 cm(-1) (5.29 eV) for the C-H bond energy, a value that agrees with our quantum mechanical calculations. Published by Elsevier B.V.

  13. Efficacy of hamstring stretching programs in schoolchildren. A systematic review

    Directory of Open Access Journals (Sweden)

    Carlos-Alberto BECERRA FERNANDEZ

    2017-03-01

    Full Text Available The main purpose of the present review was to examine the scientific literature on the effects of physical education-based stretching programs on hamstring extensibility in schoolchildren aged 6-11 years. For this purpose relevant studies were searched from ten electronic databases dated up through May 2015. Of the 25 potentially relevant articles identified and retrieved for more detailed evaluation, only eight studies were included in the present review because they met the inclusion criteria. The overall results showed that incorporating hamstring stretching as a part of physical education classes produces a significant improvement in the scores of the tests: straight leg raise and classic sit-and-reach, for the experimental groups, but not for control groups. Stretching programs can be included in Physical Education classes, specifically during the warm-up and the cool down periods in order to improve hamstring extensibility. Although it seems that the stretching exercises in the warm-up period could be less effective in gaining flexibility in school children. Studies that use a stretching volume between 4 and 7 minutes per session and 2-4 training classes per week, obtain statistically significant improvements on the levels of hamstring flexibility in the experimental groups. However, after a five-week detraining period, children revert back to their initial flexibility levels. Therefore, it seems appropriate that physical education teachers should implement stretching programs to improve the students´ flexibility during the Physical Education classes.

  14. Optical stretching on chip with acoustophoretic prefocusing

    DEFF Research Database (Denmark)

    Khoury Arvelo, Maria; Laub Busk, L.; Bruus, Henrik

    2012-01-01

    prefocusing. This focusing mechanism aims for target particles to always ow in the correct height relative to the optical stretcher, and is induced by a piezo-electric ultrasound transducer attached underneath the chip and driven at a frequency leading to a vertical standing ultrasound wave...... in the microchannel. Trapping and manipulation is demonstrated for dielectric beads. In addition, we show trapping, manipulation and stretching of red blood cells and vesicles, whereby we extract the elastic properties of these objects. Our design points towards the construction of a low-cost, high-throughput lab-on-a-chip...

  15. Time stretch and its applications

    Science.gov (United States)

    Mahjoubfar, Ata; Churkin, Dmitry V.; Barland, Stéphane; Broderick, Neil; Turitsyn, Sergei K.; Jalali, Bahram

    2017-06-01

    Observing non-repetitive and statistically rare signals that occur on short timescales requires fast real-time measurements that exceed the speed, precision and record length of conventional digitizers. Photonic time stretch is a data acquisition method that overcomes the speed limitations of electronic digitizers and enables continuous ultrafast single-shot spectroscopy, imaging, reflectometry, terahertz and other measurements at refresh rates reaching billions of frames per second with non-stop recording spanning trillions of consecutive frames. The technology has opened a new frontier in measurement science unveiling transient phenomena in nonlinear dynamics such as optical rogue waves and soliton molecules, and in relativistic electron bunching. It has also created a new class of instruments that have been integrated with artificial intelligence for sensing and biomedical diagnostics. We review the fundamental principles and applications of this emerging field for continuous phase and amplitude characterization at extremely high repetition rates via time-stretch spectral interferometry.

  16. Lamellar thickness and stretching temperature dependency of cavitation in semicrystalline polymers.

    Directory of Open Access Journals (Sweden)

    Yaotao Wang

    Full Text Available Polybutene-1 (PB-1, a typical semicrystalline polymer, in its stable form I shows a peculiar temperature dependent strain-whitening behavior when being stretched at temperatures in between room temperature and melting temperature of the crystallites where the extent of strain-whitening weakens with the increasing of stretching temperature reaching a minima value followed by an increase at higher stretching temperatures. Correspondingly, a stronger strain-hardening phenomenon was observed at higher temperatures. The strain-whitening phenomenon in semicrystalline polymers has its origin of cavitation process during stretching. In this work, the effect of crystalline lamellar thickness and stretching temperature on the cavitation process in PB-1 has been investigated by means of combined synchrotron ultrasmall-angle and wide-angle X-ray scattering techniques. Three modes of cavitation during the stretching process can be identified, namely "no cavitation" for the quenched sample with the thinnest lamellae where only shear yielding occurred, "cavitation with reorientation" for the samples stretched at lower temperatures and samples with thicker lamellae, and "cavitation without reorientation" for samples with thinner lamellae stretched at higher temperatures. The mode "cavitation with reorientation" occurs before yield point where the plate-like cavities start to be generated within the lamellar stacks with normal perpendicular to the stretching direction due to the blocky substructure of the crystalline lamellae and reorient gradually to the stretching direction after strain-hardening. The mode of "cavitation without reorientation" appears after yield point where ellipsoidal shaped cavities are generated in those lamellae stacks with normal parallel to the stretching direction followed by an improvement of their orientation at larger strains. X-ray diffraction results reveal a much improved crystalline orientation for samples with thinner lamellae

  17. Lamellar thickness and stretching temperature dependency of cavitation in semicrystalline polymers.

    Science.gov (United States)

    Wang, Yaotao; Jiang, Zhiyong; Fu, Lianlian; Lu, Ying; Men, Yongfeng

    2014-01-01

    Polybutene-1 (PB-1), a typical semicrystalline polymer, in its stable form I shows a peculiar temperature dependent strain-whitening behavior when being stretched at temperatures in between room temperature and melting temperature of the crystallites where the extent of strain-whitening weakens with the increasing of stretching temperature reaching a minima value followed by an increase at higher stretching temperatures. Correspondingly, a stronger strain-hardening phenomenon was observed at higher temperatures. The strain-whitening phenomenon in semicrystalline polymers has its origin of cavitation process during stretching. In this work, the effect of crystalline lamellar thickness and stretching temperature on the cavitation process in PB-1 has been investigated by means of combined synchrotron ultrasmall-angle and wide-angle X-ray scattering techniques. Three modes of cavitation during the stretching process can be identified, namely "no cavitation" for the quenched sample with the thinnest lamellae where only shear yielding occurred, "cavitation with reorientation" for the samples stretched at lower temperatures and samples with thicker lamellae, and "cavitation without reorientation" for samples with thinner lamellae stretched at higher temperatures. The mode "cavitation with reorientation" occurs before yield point where the plate-like cavities start to be generated within the lamellar stacks with normal perpendicular to the stretching direction due to the blocky substructure of the crystalline lamellae and reorient gradually to the stretching direction after strain-hardening. The mode of "cavitation without reorientation" appears after yield point where ellipsoidal shaped cavities are generated in those lamellae stacks with normal parallel to the stretching direction followed by an improvement of their orientation at larger strains. X-ray diffraction results reveal a much improved crystalline orientation for samples with thinner lamellae stretched at higher

  18. Stretching

    Science.gov (United States)

    ... this topic for: Teens Dehydration Safety Tips: Running Knee Injuries Repetitive Stress Injuries Sports and Exercise Safety Dealing With Sports Injuries Sports Center Strains and Sprains View more Partner Message About Us Contact Us ...

  19. The acute effect of static and dynamic stretching during warm-ups on anaerobic performance in trained women

    Directory of Open Access Journals (Sweden)

    rouhollah haghshenas

    2014-09-01

    Full Text Available The purpose of this study was to investigate effects of static stretching, dynamic stretching and no stretching methods on power and speed in volleyball players. Therefore, Twenty-four volleyball players (height: 173.29 ± 7.81 m; mass: 62.12 ± 8.73 kg; age: 22.66 ± 4.02 years; experience: 3.27 ± 6.37 were tested for speed performance using the 20 meter sprint test and also for power using vertical jump test after static stretching, dynamic stretching and no stretching. The results analyzed using ANOVA showed that There was a significant increase in height jump after dynamic stretching against static stretching. But, there were no significant differences between no stretching and static stretching groups. In addition, there was a significant decrease in time 20 meter sprint after dynamic stretching against static stretching and no stretching groups. The results of this study suggest that it may be desirable for volleyball players to perform dynamic exercises before the performance of activities that require a high power output.

  20. Measurement of skin stretch using digital image speckle correlation.

    Science.gov (United States)

    Staloff, Isabelle Afriat; Rafailovitch, Miriam

    2008-08-01

    The surface of the skin is covered by intersecting grooves and ridges which produce characteristic skin surface patterns. It has been suggested that these folds provide a reserve of tissue, allowing the skin to stretch during normal muscle movements. More so, skin is anisotropic and under constant tension. Therefore, to characterize skin displacement following stretch, a discrete, description of the in-plane skin displacement during stretch is of interest. We introduce the use of digital image speckle correlation (DISC), a non-contact technique, to map, in two dimensions, the surface deformation patterns resulting from skin stretching. We analyze skin stretch under the mechanical action of a film former applied on a defined square surface on the back of the hand. This is achieved by taking a series of images, during the drying process of the film former. The images are then analyzed with DISC to create vector diagram and projection maps, from which we can obtain spatially resolved information regarding the skin displacement. We first show that DISC can provide spatially resolved information at any time point during the drying process: areas of de-wetting, wetting were identified using projection maps; we then extracted the value of the drying time. Finally using a vector map, we show the orientation of the skin displacement during stretching and calculated the magnitude of the total stretch. We have shown previously that DISC can be used to determine skin mechanical properties and muscular activity. We show here that DISC, as a non-contact technique, can map, in two dimensions, the surface deformation patterns of a polymer solution on a substrate at any time point during the drying process. DISC analysis generates for each speckle of the sample analyzed, the orientation and magnitude of displacement of the polymer solution. DISC can map in two dimensions the deformation undergone by the substrate and skin stretch is measured in this particular case. We therefore

  1. Solving Cracking Phenomenon in Premium Transparent Toilet Soap Production Using Stretched LLDPE Film Wrap

    Science.gov (United States)

    Mat Sharif, Zainon Binti; Taib, Norhasnina Binti Mohd; Yusof, Mohd Sallehuddin Bin; Rahim, Mohammad Zulafif Bin; Tobi, Abdul Latif Bin Mohd; Othman, Mohd Syafiq Bin

    2017-05-01

    Cracking phenomenon in soap production is an imminent problem. It renders the soap aesthetically unpleasing. This study attempts to find best solution to solve cracking phenomenon in premium soap production. The adopted approach is a stamping method with stretched LLDPE wrap film. The result shows that stretched LLDPE wrap film able to solve the cracking problem. The appearance of the premium transparent was improved. This paper presents the results and the SOP for stretched LLDPE film wrap for soap making industries to adopt.

  2. Effect of stretching techniques on hamstring flexibility in female ...

    African Journals Online (AJOL)

    Flexibility can be achieved by a variety of stretching techniques and the benefits of stretching are known. However, controversy remains about the best type of stretching for achieving a particular goal or outcome. The four most basic stretches are static stretching, dynamic stretching, PNF hold-relax and PNF contract-relax ...

  3. Effects of Static and Dynamic Stretching on the Isokinetic Peak Torques and Electromyographic Activities of the Antagonist Muscles

    Science.gov (United States)

    Serefoglu, Abdullah; Sekir, Ufuk; Gür, Hakan; Akova, Bedrettin

    2017-01-01

    of the non-stretched agonist quadriceps or hamstring muscles. Key points The effects of dynamic stretching of the antagonist muscles on strength performance are unknown. We showed that both static and dynamic stretching of the antagonist muscle does not influence strength and EMG activities in the agonist muscles. Further research should focus on the effects of antagonist stretching using other techniques like PNF or ballistic stretching and/or different volumes of stretching. PMID:28344445

  4. Bending and stretching of plates

    CERN Document Server

    Mansfield, E H; Hemp, W S

    1964-01-01

    The Bending and Stretching of Plates deals with elastic plate theory, particularly on small- and large-deflexion theory. Small-deflexion theory concerns derivation of basic equations, rectangular plates, plates of various shapes, plates whose boundaries are amenable to conformal transformation, plates with variable rigidity, and approximate methods. Large-deflexion theory includes general equations and some exact solutions, approximate methods in large-deflexion theory, asymptotic large-deflexion theories for very thin plates. Asymptotic theories covers membrane theory, tension field theory, a

  5. Stretching of macromolecules and proteins

    International Nuclear Information System (INIS)

    Strick, T R; Dessinges, M-N; Charvin, G; Dekker, N H; Allemand, J-F; Bensimon, D; Croquette, V

    2003-01-01

    In this paper we review the biophysics revealed by stretching single biopolymers. During the last decade various techniques have emerged allowing micromanipulation of single molecules and simultaneous measurements of their elasticity. Using such techniques, it has been possible to investigate some of the interactions playing a role in biology. We shall first review the simplest case of a non-interacting polymer and then present the structural transitions in DNA, RNA and proteins that have been studied by single-molecule techniques. We shall explain how these techniques permit a new approach to the protein folding/unfolding transition

  6. To Stretch and Search for Better Ways

    Science.gov (United States)

    Moore, John W.

    2000-06-01

    Ambassadors. The response has been wonderful. Many people are willing and eager to show others what JCE has to offer and encourage them to subscribe. The program began in the latter half of 1999, and there were 37 Journal Ambassadors by year's end. Some are located as far away as South America and Europe, and requests for information packets for meetings and workshops now arrive several times a week. We thank everyone who has been involved in this program for getting it off to a great start. Our authors and reviewers actively search for better ways to teach chemistry and for better ways to communicate to other teachers what they have learned. This enriches their own classes first and then a much wider audience. Others have volunteered to help make JCE articles easier to find and more accessible on the Web. The ACS student affiliates at one college have taken on the project of assigning keywords to articles published in some of the years before 1995. We will add these to the JCE Index online, making it an even more effective means for finding articles on specified topics. There are many possibilities for collaboration with JCE. If you would like to contribute to an ongoing project or would like to initiate a new one, please let us know. We welcome anyone who would like to help us make this Journal better. It is important that students learn how to stretch and search for better ways. This will not happen unless we challenge them within a humane and supportive learning environment. We should expect more than memorization or unthinking application of algorithmic solutions to exercises. We should provide means by which those who do not succeed at first can try again and again. And we should provide an intellectual scaffold for those whose climb toward understanding is difficult. These are not easy goals to achieve, but the more we try and the more we communicate with others who are attempting similar tasks, the more likely we are to be successful. Most important of all is that

  7. STATIC VERSUS PNF STRETCHING IN HAMSTRING FLEXIBILITY-A COMPARATIVE STUDY

    Directory of Open Access Journals (Sweden)

    Venkata Naga Prahalada Karnati

    2015-06-01

    Full Text Available Background: Stretching used as a technique for injury prevention in the clinical settings, the study aimed to determine the early findings of hamstring tightness with both groups in the population, now a days the sedentary activities like prolonged sitting might cause hamstring tightness and change in path kinematics of gait intern lead to postural defects and back pain, understanding of the stretching helps clinician to make decisions for rehabilitation. Methods: Across-sectional study, counterbalanced with repeated-measures , one group with static stretch – (double hamstring stretch and hurdlers stretch for 3 times,30seconds subsequently in another group PNF contract relax(agonist contraction technique for 10 seconds position and 10 seconds stretch repeated for 3 times. Results: The results from data and statistical analysis by using t-test, SPSS obtained by using goniometer are tabulated in terms of mean, standard deviation and p-value in both groups. In experimental group flexion with PNF showed improvement 9.27±1.91(right side, 9.53±2.42(left side and static stretching showed 7.8±2.91(right side, 7.47±1.96(left side this proves that PNF has consistent improvement than static stretching. Conclusions: Static and proprioceptive neuromuscular facilitation stretching both have produced greater improvement but compared with PNF contract relax(agonist stretching showed significant change in hamstring flexibility compared with control group . The effect sizes, however corresponding to these stretching-induced changes were small, which suggests the need for practitioners to consider a risk-to-benefit ratio when incorporating static or proprioceptive neuromuscular facilitation stretching.

  8. Can Treadmill Perturbations Evoke Stretch Reflexes in the Calf Muscles?

    Science.gov (United States)

    Sloot, Lizeth H; van den Noort, Josien C; van der Krogt, Marjolein M; Bruijn, Sjoerd M; Harlaar, Jaap

    2015-01-01

    Disinhibition of reflexes is a problem amongst spastic patients, for it limits a smooth and efficient execution of motor functions during gait. Treadmill belt accelerations may potentially be used to measure reflexes during walking, i.e. by dorsal flexing the ankle and stretching the calf muscles, while decelerations show the modulation of reflexes during a reduction of sensory feedback. The aim of the current study was to examine if belt accelerations and decelerations of different intensities applied during the stance phase of treadmill walking can evoke reflexes in the gastrocnemius, soleus and tibialis anterior in healthy subjects. Muscle electromyography and joint kinematics were measured in 10 subjects. To determine whether stretch reflexes occurred, we assessed modelled musculo-tendon length and stretch velocity, the amount of muscle activity, as well as the incidence of bursts or depressions in muscle activity with their time delays, and co-contraction between agonist and antagonist muscle. Although the effect on the ankle angle was small with 2.8±1.0°, the perturbations caused clear changes in muscle length and stretch velocity relative to unperturbed walking. Stretched muscles showed an increasing incidence of bursts in muscle activity, which occurred after a reasonable electrophysiological time delay (163-191 ms). Their amplitude was related to the muscle stretch velocity and not related to co-contraction of the antagonist muscle. These effects increased with perturbation intensity. Shortened muscles showed opposite effects, with a depression in muscle activity of the calf muscles. The perturbations only slightly affected the spatio-temporal parameters, indicating that normal walking was retained. Thus, our findings showed that treadmill perturbations can evoke reflexes in the calf muscles and tibialis anterior. This comprehensive study could form the basis for clinical implementation of treadmill perturbations to functionally measure reflexes during

  9. Can Treadmill Perturbations Evoke Stretch Reflexes in the Calf Muscles?

    Directory of Open Access Journals (Sweden)

    Lizeth H Sloot

    Full Text Available Disinhibition of reflexes is a problem amongst spastic patients, for it limits a smooth and efficient execution of motor functions during gait. Treadmill belt accelerations may potentially be used to measure reflexes during walking, i.e. by dorsal flexing the ankle and stretching the calf muscles, while decelerations show the modulation of reflexes during a reduction of sensory feedback. The aim of the current study was to examine if belt accelerations and decelerations of different intensities applied during the stance phase of treadmill walking can evoke reflexes in the gastrocnemius, soleus and tibialis anterior in healthy subjects. Muscle electromyography and joint kinematics were measured in 10 subjects. To determine whether stretch reflexes occurred, we assessed modelled musculo-tendon length and stretch velocity, the amount of muscle activity, as well as the incidence of bursts or depressions in muscle activity with their time delays, and co-contraction between agonist and antagonist muscle. Although the effect on the ankle angle was small with 2.8±1.0°, the perturbations caused clear changes in muscle length and stretch velocity relative to unperturbed walking. Stretched muscles showed an increasing incidence of bursts in muscle activity, which occurred after a reasonable electrophysiological time delay (163-191 ms. Their amplitude was related to the muscle stretch velocity and not related to co-contraction of the antagonist muscle. These effects increased with perturbation intensity. Shortened muscles showed opposite effects, with a depression in muscle activity of the calf muscles. The perturbations only slightly affected the spatio-temporal parameters, indicating that normal walking was retained. Thus, our findings showed that treadmill perturbations can evoke reflexes in the calf muscles and tibialis anterior. This comprehensive study could form the basis for clinical implementation of treadmill perturbations to functionally

  10. PROPRIOCEPTIVE NEUROMUSCULAR FACILITATION STRETCHING VERSUS STATIC STRETCHING ON SPRINTING PERFORMANCE AMONG COLLEGIATE SPRINTERS

    Directory of Open Access Journals (Sweden)

    Jayaram Maharjan

    2015-08-01

    Full Text Available Background: A warm-up is important part of preparation for sprinting. There is popularity of doing stretching as part of warm up before athletic activity. The static stretching and PNF stretching is performed by athletes but their effectiveness on sprinting performance is in state of debate. The objective is to determine the effect of static stretching and PNF stretching on sprinting performance in college sprinters and to compare the effects of PNF stretching over static stretching on sprinting performance in college sprinters. Method: A total of 100 subjects were taken for the study that fulfill the inclusion criteria and all were divided into group- A (static stretching and group- B (PNF stretching by simple random sampling method. Both the groups received 5 minutes of warm-up exercises. Pre-Post design was used, which consisted of running a 40-yard sprint immediately following 2 stretching conditions aimed at the lower limb muscles Results: In static stretching group sprint time changed from 6.55 with standard deviation of 0.93 to 6.12 with standard deviation of 1.02 (P.605. Conclusion: Hence both static stretching and PNF stretching can be performed before sprinting activity to improve the sprinting performance.

  11. Stretching, twisting and supercoiling in short, single DNA molecules

    Science.gov (United States)

    Lam, Pui-Man; Zhen, Yi

    2018-02-01

    We had combined the Neukirch-Marko model that describes the extension, torque and supercoiling in single, stretched and twisted DNA of infinite contour length, with a form of the free energy suggested by Sinha and Samuels to describe short DNA, with contour length only a few times the persistence length. We find that the free energy of the stretched but untwisted DNA, is significantly modified from its infinitely length value and this in turn modifies significantly the torque and supercoiling. We show that this is consistent with short DNA being more flexible than infinitely long DNA. We hope our results will stimulate experimental investigation of torque and supercoiling in short DNA.

  12. Rat cutaneous RA afferents activated by two-dimensional skin stretch.

    Science.gov (United States)

    Grigg, Peter; Robichaud, Daniel R

    2004-07-01

    Skin develops biaxial stresses and strains when stretched. Rapidly adapting cutaneous mechanoreceptor neurons are known to be stretch sensitive, yet in the past, they have been studied using stretch stimuli applied along only a single direction. In this study, cutaneous rapidly adapting mechanoreceptors were studied in preparations of isolated skin in which the skin was stretched dynamically using biaxial stretch stimuli and in which loads and displacements were measured along two directions. Stretch stimuli followed a pseudo-Gaussian waveform and were applied along either one or two directions simultaneously. Associations between spikes and mechanical variables were determined using multiple logistic regression. When the skin was actuated along a single direction, holding the orthogonal axis fixed, spike responses were strongly associated with mechanical variables along the actuated direction. The variables were stress and its rate of change, the rate of change of strain, and the product of stress and its rate of change, which is proportional to strain energy density. When the skin was stretched along a single direction, spikes were very poorly associated with stress variables measured along the direction orthogonal to the stretch. Afferents showed weak directional selectivity: they were slightly more responsive to the variable stress along the circumferential direction of the hindlimb. When the skin was stretched biaxially (i.e., along both directions simultaneously) with identical pseudo-Gaussian noise stimuli, neuronal responses were associated with the same variables as above, but the associations were weaker.

  13. Cooperativity among short amyloid stretches in long amyloidogenic sequences.

    Directory of Open Access Journals (Sweden)

    Lele Hu

    Full Text Available Amyloid fibrillar aggregates of polypeptides are associated with many neurodegenerative diseases. Short peptide segments in protein sequences may trigger aggregation. Identifying these stretches and examining their behavior in longer protein segments is critical for understanding these diseases and obtaining potential therapies. In this study, we combined machine learning and structure-based energy evaluation to examine and predict amyloidogenic segments. Our feature selection method discovered that windows consisting of long amino acid segments of ~30 residues, instead of the commonly used short hexapeptides, provided the highest accuracy. Weighted contributions of an amino acid at each position in a 27 residue window revealed three cooperative regions of short stretch, resemble the β-strand-turn-β-strand motif in A-βpeptide amyloid and β-solenoid structure of HET-s(218-289 prion (C. Using an in-house energy evaluation algorithm, the interaction energy between two short stretches in long segment is computed and incorporated as an additional feature. The algorithm successfully predicted and classified amyloid segments with an overall accuracy of 75%. Our study revealed that genome-wide amyloid segments are not only dependent on short high propensity stretches, but also on nearby residues.

  14. Anisotropic instability of a stretching film

    Science.gov (United States)

    Xu, Bingrui; Li, Minhao; Deng, Daosheng

    2017-11-01

    Instability of a thin liquid film, such as dewetting arising from Van der Waals force, has been well studied, and is typically characterized by formation of many droplets. Interestingly, a thin liquid film subjected to an applied stretching during a process of thermal drawing is evolved into an array of filaments, i.e., continuity is preserved along the direction of stretching while breakup occurs exclusively in the plane of cross section. Here, to understand this anisotropic instability, we build a physical model by considering both Van der Waals force and the effect of stretching. By using the linear instability analysis method and then performing a numerical calculation, we find that the growth rate of perturbations at the cross section is larger than that along the direction of stretching, resulting in the anisotropic instability of the stretching film. These results may provide theoretical guidance to achieve more diverse structures for nanotechnology.

  15. Stretching to prevent or reduce muscle soreness after exercise.

    Science.gov (United States)

    Herbert, Robert D; de Noronha, Marcos; Kamper, Steven J

    2011-07-06

    Many people stretch before or after engaging in athletic activity. Usually the purpose is to reduce risk of injury, reduce soreness after exercise, or enhance athletic performance. This is an update of a Cochrane review first published in 2007. The aim of this review was to determine effects of stretching before or after exercise on the development of delayed-onset muscle soreness. We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (to 10 August 2009), the Cochrane Central Register of Controlled Trials (2010, Issue 1), MEDLINE (1966 to 8th February 2010), EMBASE (1988 to 8th February 2010), CINAHL (1982 to 23rd February 2010), SPORTDiscus (1949 to 8th February 2010), PEDro (to 15th February 2010) and reference lists of articles. Eligible studies were randomised or quasi-randomised studies of any pre-exercise or post-exercise stretching technique designed to prevent or treat delayed-onset muscle soreness (DOMS). For the studies to be included, the stretching had to be conducted soon before or soon after exercise and muscle soreness had to be assessed. Risk of bias was assessed using The Cochrane Collaboration's 'Risk of bias' tool and quality of evidence was assessed using GRADE. Estimates of effects of stretching were converted to a common 100-point scale. Outcomes were pooled in fixed-effect meta-analyses. Twelve studies were included in the review. This update incorporated two new studies. One of the new trials was a large field-based trial that included 2377 participants, 1220 of whom were allocated stretching. All other 11 studies were small, with between 10 and 30 participants receiving the stretch condition. Ten studies were laboratory-based and other two were field-based. All studies were exposed to either a moderate or high risk of bias. The quality of evidence was low to moderate.There was a high degree of consistency of results across studies. The pooled estimate showed that pre-exercise stretching reduced soreness at one

  16. Foliar δ13C Showed No Altitudinal Trend in an Arid Region and Atmospheric Pressure Exerted a Negative Effect on Plant δ13C.

    Science.gov (United States)

    Chen, Zixun; Wang, Guoan; Jia, Yufu

    2017-01-01

    Previous studies have suggested foliar δ 13 C generally increases with altitude. However, some observations reported no changes or even decreased trends in foliar δ 13 C. We noted that all the studies in which δ 13 C increased with elevation were conducted in the human regions, whereas those investigations in which δ 13 C did not vary or decreased were conducted in areas with water stress. Thus, we proposed that the pattern of increasing δ 13 C with elevation is not a general one, and that δ 13 C may remain unchanged or decrease in plants grown in arid environments. To test the hypothesis, we sampled plants along altitude gradients on the shady and sunny slopes of Mount Tianshan characterized by arid and semiarid climates. The measurements of foliar δ 13 C showed no altitudinal trends for the plants grown on either of the slopes. Therefore, this study supported our hypothesis. In addition, the present study addressed the effect of atmospheric pressure on plant δ 13 C by accounting for the effects of temperature and precipitation on δ 13 C. This study found that the residual foliar δ 13 C increased with increasing altitude, suggesting that atmospheric pressure played a negative role in foliar δ 13 C.

  17. The Effect of Lithotomy Position on Nerve Stretch: A Cadaveric Study.

    Science.gov (United States)

    Deveneau, Nicolette E; Forbis, Courtney; Lipetskaia, Lioudmilla; Kinman, Casey L; Agrawal, Anubhav; Herring, Nicole R; Francis, Sean L

    The objective of our study was to design a method to measure nerve stretch in cadaveric subjects and then use the method to assess femoral nerve stretch in the lithotomy position with varying degrees of flexion and extension. A university-based, cadaveric observational study of femoral nerve stretch was conducted. In 6 cadaveric subjects, femoral nerve near the inguinal ligament was dissected in each cadaveric subject. The nerve was marked, and digital images of the nerve were obtained in the supine position and lithotomy position in both flexion and extension. Distances were calculated using the ratio of pixels to millimeter specific for each image. The average distance for each set of images was then used to calculate the percent change from supine for each position. We were able to assess nerve stretch using photo-editing software. For extended position, all nerves showed some degree of stretch with the mean percent change in nerve length being 10.35%. For all other positions, most showed a decrease of nerve length. There was not a significant relation between degree of extension and stretch (Pearson r, P < 0.05). Hip extension between 10 and 20 degrees consistently stretches the femoral nerve greater than 5%. The potential for femoral nerve stretch and avoiding hip extension should be considered when positioning a patient in lithotomy for surgical procedures.

  18. Stretching skeletal muscle: chronic muscle lengthening through sarcomerogenesis.

    Directory of Open Access Journals (Sweden)

    Alexander M Zöllner

    Full Text Available Skeletal muscle responds to passive overstretch through sarcomerogenesis, the creation and serial deposition of new sarcomere units. Sarcomerogenesis is critical to muscle function: It gradually re-positions the muscle back into its optimal operating regime. Animal models of immobilization, limb lengthening, and tendon transfer have provided significant insight into muscle adaptation in vivo. Yet, to date, there is no mathematical model that allows us to predict how skeletal muscle adapts to mechanical stretch in silico. Here we propose a novel mechanistic model for chronic longitudinal muscle growth in response to passive mechanical stretch. We characterize growth through a single scalar-valued internal variable, the serial sarcomere number. Sarcomerogenesis, the evolution of this variable, is driven by the elastic mechanical stretch. To analyze realistic three-dimensional muscle geometries, we embed our model into a nonlinear finite element framework. In a chronic limb lengthening study with a muscle stretch of 1.14, the model predicts an acute sarcomere lengthening from 3.09[Formula: see text]m to 3.51[Formula: see text]m, and a chronic gradual return to the initial sarcomere length within two weeks. Compared to the experiment, the acute model error was 0.00% by design of the model; the chronic model error was 2.13%, which lies within the rage of the experimental standard deviation. Our model explains, from a mechanistic point of view, why gradual multi-step muscle lengthening is less invasive than single-step lengthening. It also explains regional variations in sarcomere length, shorter close to and longer away from the muscle-tendon interface. Once calibrated with a richer data set, our model may help surgeons to prevent muscle overstretch and make informed decisions about optimal stretch increments, stretch timing, and stretch amplitudes. We anticipate our study to open new avenues in orthopedic and reconstructive surgery and enhance

  19. Strategy as stretch and leverage.

    Science.gov (United States)

    Hamel, G; Prahalad, C K

    1993-01-01

    Global competition is not just product versus product or company versus company. It is mind-set versus mind-set. Driven to understand the dynamics of competition, we have learned a lot about what makes one company more successful than another. But to find the root of competitiveness--to understand why some companies create new forms of competitive advantage while others watch and follow--we must look at strategic mind-sets. For many managers, "being strategic" means pursuing opportunities that fit the company's resources. This approach is not wrong, Gary Hamel and C.K. Prahalad contend, but it obscures an approach in which "stretch" supplements fit and being strategic means creating a chasm between ambition and resources. Toyota, CNN, British Airways, Sony, and others all displaced competitors with stronger reputations and deeper pockets. Their secret? In each case, the winner had greater ambition than its well-endowed rivals. Winners also find less resource-intensive ways of achieving their ambitious goals. This is where leverage complements the strategic allocation of resources. Managers at competitive companies can get a bigger bang for their buck in five basic ways: by concentrating resources around strategic goals; by accumulating resources more efficiently; by complementing one kind of resource with another; by conserving resources whenever they can; and by recovering resources from the market-place as quickly as possible. As recent competitive battles have demonstrated, abundant resources can't guarantee continued industry leadership.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Deep neural networks show an equivalent and often superior performance to dermatologists in onychomycosis diagnosis: Automatic construction of onychomycosis datasets by region-based convolutional deep neural network.

    Directory of Open Access Journals (Sweden)

    Seung Seog Han

    Full Text Available Although there have been reports of the successful diagnosis of skin disorders using deep learning, unrealistically large clinical image datasets are required for artificial intelligence (AI training. We created datasets of standardized nail images using a region-based convolutional neural network (R-CNN trained to distinguish the nail from the background. We used R-CNN to generate training datasets of 49,567 images, which we then used to fine-tune the ResNet-152 and VGG-19 models. The validation datasets comprised 100 and 194 images from Inje University (B1 and B2 datasets, respectively, 125 images from Hallym University (C dataset, and 939 images from Seoul National University (D dataset. The AI (ensemble model; ResNet-152 + VGG-19 + feedforward neural networks results showed test sensitivity/specificity/ area under the curve values of (96.0 / 94.7 / 0.98, (82.7 / 96.7 / 0.95, (92.3 / 79.3 / 0.93, (87.7 / 69.3 / 0.82 for the B1, B2, C, and D datasets. With a combination of the B1 and C datasets, the AI Youden index was significantly (p = 0.01 higher than that of 42 dermatologists doing the same assessment manually. For B1+C and B2+ D dataset combinations, almost none of the dermatologists performed as well as the AI. By training with a dataset comprising 49,567 images, we achieved a diagnostic accuracy for onychomycosis using deep learning that was superior to that of most of the dermatologists who participated in this study.

  1. Stretched versus compressed exponential kinetics in α-helix folding

    International Nuclear Information System (INIS)

    Hamm, Peter; Helbing, Jan; Bredenbeck, Jens

    2006-01-01

    In a recent paper (J. Bredenbeck, J. Helbing, J.R. Kumita, G.A. Woolley, P. Hamm, α-helix formation in a photoswitchable peptide tracked from picoseconds to microseconds by time resolved IR spectroscopy, Proc. Natl. Acad. Sci USA 102 (2005) 2379), we have investigated the folding of a photo-switchable α-helix with a kinetics that could be fit by a stretched exponential function exp(-(t/τ) β ). The stretching factor β became smaller as the temperature was lowered, a result which has been interpreted in terms of activated diffusion on a rugged energy surface. In the present paper, we discuss under which conditions diffusion problems occur with stretched exponential kinetics (β 1). We show that diffusion problems do have a strong tendency to yield stretched exponential kinetics, yet, that there are conditions (strong perturbation from equilibrium, performing the experiment in the folding direction) under which compressed exponential kinetics would be expected instead. We discuss the kinetics on free energy surfaces predicted by simple initiation-propagation models (zipper models) of α-helix folding, as well as by folding funnel models. We show that our recent experiment has been performed under condition for which models with strong downhill driving force, such as the zipper model, would predict compressed, rather than stretched exponential kinetics, in disagreement with the experimental observation. We therefore propose that the free energy surface along a reaction coordinate that governs the folding kinetics must be relatively flat and has a shape similar to a 1D golf course. We discuss how this conclusion can be unified with the thermodynamically well established zipper model by introducing an additional kinetic reaction coordinate

  2. Static vs. Dynamic Acute Stretching Effect on Quadriceps Muscle Activity during Soccer Instep Kicking

    Science.gov (United States)

    Amiri-Khorasani, Mohammadtaghi; Kellis, Eleftherios

    2013-01-01

    The purpose of this study was to compare the effects of static and dynamic stretching on quadriceps muscle activation during maximal soccer instep kicking. The kicking motion of twelve male college soccer players (body height: 174.66 ± 5.01 cm; body mass: 72.83 ± 4.83 kg; age: 18.83 ± 0.75 years) was captured using six synchronized high-speed infra-red cameras whilst electromyography (EMG) signals from vastus medialis (VM), lateralis (VL) and rectus femoris (RF) were recorded before and after static or dynamic stretching. Analysis of variance designs showed a higher increase in knee extension angular velocity (9.65% vs. −1.45%, p stretching exercises. Based on these results, it could be suggested that dynamic stretching is probably more effective in increasing quadriceps muscle activity and knee extension angular velocity during the final swing phase of a maximal soccer instep kick than static stretching. PMID:24511339

  3. Mechanical stretch modulates microRNA 21 expression, participating in proliferation and apoptosis in cultured human aortic smooth muscle cells.

    Directory of Open Access Journals (Sweden)

    Jian tao Song

    Full Text Available OBJECTIVES: Stretch affects vascular smooth muscle cell proliferation and apoptosis, and several responsible genes have been proposed. We tested whether the expression of microRNA 21 (miR-21 is modulated by stretch and is involved in stretch-induced proliferation and apoptosis of human aortic smooth muscle cells (HASMCs. METHODS AND RESULTS: RT-PCR revealed that elevated stretch (16% elongation, 1 Hz increased miR-21 expression in cultured HASMCs, and moderate stretch (10% elongation, 1 Hz decreased the expression. BrdU incorporation assay and cell counting showed miR-21 involved in the proliferation of HASMCs mediated by stretch, likely by regulating the expression of p27 and phosphorylated retinoblastoma protein (p-Rb. FACS analysis revealed that the complex of miR-21 and programmed cell death protein 4 (PDCD4 participated in regulating apoptosis with stretch. Stretch increased the expression of primary miR-21 and pre-miR-21 in HASMCs. Electrophoretic mobility shift assay (EMSA demonstrated that stretch increased NF-κB and AP-1 activities in HASMCs, and blockade of AP-1 activity by c-jun siRNA significantly suppressed stretch-induced miR-21 expression. CONCLUSIONS: Cyclic stretch modulates miR-21 expression in cultured HASMCs, and miR-21 plays important roles in regulating proliferation and apoptosis mediated by stretch. Stretch upregulates miR-21 expression at least in part at the transcription level and AP-1 is essential for stretch-induced miR-21 expression.

  4. Comparison of 2 Dosages of Stretching Treatment in Infants with Congenital Muscular Torticollis: A Randomized Trial.

    Science.gov (United States)

    He, Lu; Yan, Xiaohua; Li, Jinling; Guan, Buyun; Ma, Liying; Chen, Ying; Mai, Jianning; Xu, Kaishou

    2017-05-01

    To compare the short-term efficacy of 2 dosages of stretching treatment on the clinical outcomes in infants with congenital muscular torticollis. This was a prospective randomized controlled study. Fifty infants with congenital muscular torticollis who were randomly assigned to 100-times stretching group and 50-times stretching group received stretching treatment for the affected sternocleidomastoid muscle. The outcomes including the head tilt, the cervical passive range of motion, and the muscle function of cervical lateral flexors determined by the muscle function scale were assessed at baseline and at 4 and 8 weeks after treatment. The sternocleidomastoid muscle growth analyzed by the thickness ratio of sternocleidomastoid muscles was measured using ultrasonography at baseline and 8 weeks after treatment. Except the ratio of muscle function scale scores, the postintervention outcomes were all significantly improved in both groups compared with baseline (P stretching group showed greater improvement compared with 50-times stretching group in head tilt and cervical passive range of motion at 4 and 8 weeks after treatment (P Stretching treatment of 2 dosages may effectively improve head tilt, cervical passive range of motion, and sternocleidomastoid muscle growth in infants with congenital muscular torticollis. The stretching treatment of 100 times per day is likely to associate with greater improvement in head tilt and cervical passive range of motion.

  5. Effect of modified hold-relax stretching and static stretching on hamstring muscle flexibility.

    Science.gov (United States)

    Ahmed, Hashim; Iqbal, Amir; Anwer, Shahnawaz; Alghadir, Ahmad

    2015-02-01

    [Purpose] The aim of present study was to compare the effectiveness of modified hold-relax stretching and static stretching in improving the hamstring muscle flexibility. [Subjects and Methods] Forty-five male subjects with hamstring tightness were included in this study. The subjects were randomly placed into three groups: the modified hold-relax stretching, static stretching and control groups. The modified hold-relax stretching group performed 7 seconds of isometric contraction and then relaxed for 5 seconds, and this was repeated five times daily for five consecutive days. The static stretching group received 10 minutes of static stretching with the help of a pulley and weight system for five consecutive days. The control group received only moist heat for 20 minutes for five consecutive days. A baseline reading of passive knee extension (PKE) was taken prior to the intervention; rest measurements were taken immediate post intervention on day 1, day 3, day 5, and after a 1 week follow-up, i.e., at the 12th day. [Results] On comparing the baseline readings of passive knee extension (PKE), there was no difference noted between the three groups. On comparing the posttest readings on day 5 between the 3 groups, a significant difference was noted. However, post hoc analysis revealed an insignificant difference between the modified hold-relax stretching and static stretching groups. There was a significant difference between the static stretching and control groups and between the modified hold-relax stretching and control groups. [Conclusion] The results of this study indicate that both the modified hold-relax stretching technique and static stretching are equally effective, as there was no significant difference in improving the hamstring muscle flexibility between the two groups.

  6. Epidemiology of dengue fever: A model with temporary cross-immunity and possible secondary infection shows bifurcations and chaotic behaviour in wide parameter regions.

    NARCIS (Netherlands)

    Aguilar, M.; Kooi, B.W.; Stollenwerk, N.

    2008-01-01

    Basic models suitable to explain the epidemiology of dengue fever have previously shown the possibility of deterministically chaotic attractors, which might explain the observed fluctuations found in empiric outbreak data. However, the region of bifurcations and chaos require strong enhanced

  7. Stretch induced endothelin-1 secretion by adult rat astrocytes involves calcium influx via stretch-activated ion channels (SACs)

    International Nuclear Information System (INIS)

    Ostrow, Lyle W.; Suchyna, Thomas M.; Sachs, Frederick

    2011-01-01

    Highlights: → Endothelin-1 expression by adult rat astrocytes correlates with cell proliferation. → Stretch-induced ET-1 is inhibited by GsMtx-4, a specific inhibitor of Ca 2+ permeant SACs. → The less specific SAC inhibitor streptomycin also inhibits ET-1 secretion. → Stretch-induced ET-1 production depends on a calcium influx. → SAC pharmacology may provide a new class of therapeutic agents for CNS pathology. -- Abstract: The expression of endothelins (ETs) and ET-receptors is often upregulated in brain pathology. ET-1, a potent vasoconstrictor, also inhibits the expression of astrocyte glutamate transporters and is mitogenic for astrocytes, glioma cells, neurons, and brain capillary endothelia. We have previously shown that mechanical stress stimulates ET-1 production by adult rat astrocytes. We now show in adult astrocytes that ET-1 production is driven by calcium influx through stretch-activated ion channels (SACs) and the ET-1 production correlates with cell proliferation. Mechanical stimulation using biaxial stretch ( 2+ threshold. This coupling of mechanical stress to the astrocyte endothelin system through SACs has treatment implications, since all pathology deforms the surrounding parenchyma.

  8. Effect of CH stretching excitation on the reaction dynamics of F + CHD{sub 3} → DF + CHD{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jiayue; Zhang, Dong; Chen, Zhen; Jiang, Bo [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian, Liaoning 116023 (China); Blauert, Florian [Dynamics at Surfaces, Faculty of Chemistry, Georg-August-Universität Göttingen, 37077 Göttingen (Germany); Dai, Dongxu; Wu, Guorong, E-mail: wugr@dicp.ac.cn, E-mail: xmyang@dicp.ac.cn; Zhang, Donghui; Yang, Xueming, E-mail: wugr@dicp.ac.cn, E-mail: xmyang@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian, Liaoning 116023 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2015-07-28

    The vibrationally excited reaction of F + CHD{sub 3}(ν{sub 1} = 1) → DF + CHD{sub 2} at a collision energy of 9.0 kcal/mol is investigated using the crossed-beams and time-sliced velocity map imaging techniques. Detailed and quantitative information of the CH stretching excitation effects on the reactivity and dynamics of the title reaction is extracted with the help of an accurate determination of the fraction of the excited CHD{sub 3} reagent in the crossed-beam region. It is found that all vibrational states of the CHD{sub 2} products observed in the ground-state reaction, which mainly involve the excitation of the umbrella mode of the CHD{sub 2} products, are severely suppressed by the CH stretching excitation. However, there are four additional vibrational states of the CHD{sub 2} products appearing in the excited-state reaction which are not presented in the ground-state reaction. These vibrational states either have the CH stretching excitation retained or involve one quantum excitation in the CH stretching and the excitation of the umbrella mode. Including all observed vibrational states, the overall cross section of the excited-state reaction is estimated to be 66.6% of that of the ground-state one. Experimental results also show that when the energy of CH stretching excitation is released during the reaction, it is deposited almost exclusively as the rovibrational energy of the DF products, with little portion in the translational degree of freedom. For vibrational states of the CHD{sub 2} products observed in both ground- and excited-state reactions, the CH stretching excitation greatly suppresses the forward scattered products, causing a noticeable change in the product angular distributions.

  9. Investing in a Large Stretch Press

    Science.gov (United States)

    Choate, M.; Nealson, W.; Jay, G.; Buss, W.

    1986-01-01

    Press for forming large aluminum parts from plates provides substantial economies. Study assessed advantages and disadvantages of investing in large stretch-forming press, and also developed procurement specification for press.

  10. Excluded Volume Effects in Gene Stretching

    OpenAIRE

    Lam, Pui-Man

    2002-01-01

    We investigate the effects excluded volume on the stretching of a single DNA in solution. We find that for small force F, the extension h is not linear in F but proportion to F^{\\chi}, with \\chi=(1-\

  11. DNA stretching on functionalized gold surfaces.

    OpenAIRE

    Zimmermann, R M; Cox, E C

    1994-01-01

    We describe a method for anchoring bacteriophage lambda DNA by one end to gold by Au-biotin-streptavidin-biotin-DNA bonds. DNA anchored to a microfabricated Au line could be aligned and stretched in flow and electric fields. The anchor was shown to resist a force of at least 11 pN, a linkage strong enough to allow DNA molecules of chromosome size to be stretched and aligned.

  12. Effects of cryotherapy and thermotherapy associated with static stretching on the flexibility of hamstring muscles

    Directory of Open Access Journals (Sweden)

    S.A. Silva

    2010-01-01

    Full Text Available The objective of the present study was to analyze the effect of cryotherapy and muscular warming on the flexibility of the hamstring muscles associated with three minutes of static stretching. Forty young male and female volunteers were randomly included in one of four groups: Group 1 – Control group, Group 2 – Three minutes of static stretching, Group 3 – Stretching preceded by warming using shortwave diathermy (20 minutes, and Group 4 – Stretching preceded by applying cryotherapy (20 minutes to the posterior thigh region. The program consisted of three series of stretching during five consecutive days and flexibility was assessed by goniometric evaluations of the extensor angle of the knee at the beginning of the protocol, at the end of the day and at the end of the protocol. The intergroup comparison was made through ANOVA post-hoc Tukey and the intragroup by paired t test, all with 5% level of significance. The three experimental groups significantly increased their range of motion in relation to the control group. However, differences were not observed among groups submitted to the different stretching programs. In conclusion, increases in flexibility were due to stretching and did not depend on previous application of hyperthermia and/or hypothermia.

  13. Comparison of two stretching methods and optimization of stretching protocol for the piriformis muscle.

    Science.gov (United States)

    Gulledge, Brett M; Marcellin-Little, Denis J; Levine, David; Tillman, Larry; Harrysson, Ola L A; Osborne, Jason A; Baxter, Blaise

    2014-02-01

    Piriformis syndrome is an uncommon diagnosis for a non-discogenic form of sciatica whose treatment has traditionally focused on stretching the piriformis muscle (PiM). Conventional stretches include hip flexion, adduction, and external rotation. Using three-dimensional modeling, we quantified the amount of (PiM) elongation resulting from two conventional stretches and we investigated by use of a computational model alternate stretching protocols that would optimize PiM stretching. Seven subjects underwent three CT scans: one supine, one with hip flexion, adduction, then external rotation (ADD stretch), and one with hip flexion, external rotation, then adduction (ExR stretch). Three-dimensional bone models were constructed from the CT scans. PiM elongation during these stretches, femoral neck inclination, femoral head anteversion, and trochanteric anteversion were measured. A computer program was developed to map PiM length over a range of hip joint positions and was validated against the measured scans. ExR and ADD stretches elongated the PiM similarly by approximately 12%. Femoral head and greater trochanter anteversion influenced PiM elongation. Placing the hip joints in 115° of hip flexion, 40° of external rotation and 25° of adduction or 120° of hip flexion, 50° of external rotation and 30° of adduction increased PiM elongation by 30-40% compared to conventional stretches (15.1 and 15.3% increases in PiM muscle length, respectively). ExR and ADD stretches elongate the PiM similarly and therefore may have similar clinical effectiveness. The optimized stretches led to larger increases in PiM length and may be more easily performed by some patients due to increased hip flexion. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

  14. Effects of proprioceptive neuromuscular facilitation stretching and static stretching on maximal voluntary contraction.

    Science.gov (United States)

    Miyahara, Yutetsu; Naito, Hisashi; Ogura, Yuji; Katamoto, Shizuo; Aoki, Junichiro

    2013-01-01

    This study was undertaken to investigate and compare the effects of proprioceptive neuromuscular facilitation (PNF) stretching and static stretching on maximal voluntary contraction (MVC). Thirteen male university students (age, 20 ± 1 years; height, 172.2 ± 4.6 cm; weight, 68.4 ± 6.7 kg; mean ± SD) completed 3 different conditions on 3 nonconsecutive days in randomized order: static stretching (SS), PNF stretching (PNF), and no stretching (control, CON). Each condition consisted of a 5-minute rest accompanied by one of the following activities: (a) control, (b) SS, or (c) PNF stretching. The hip flexion range of motion (ROM) was evaluated immediately before and after the activity. The MVC of knee flexion was then measured. Surface electromyography was recorded from the biceps femoris and vastus lateralis muscles during MVC tests and stretching. Although increases in ROM were significantly greater after PNF than after SS (p < 0.01), the decreases in MVC were similar between the 2 treatments. These results suggest that, although PNF stretching increases ROM more than SS, PNF stretching and SS is detrimental to isometric maximal strength.

  15. The Effectiveness of Neck Stretching Exercises Following Total Thyroidectomy on Reducing Neck Pain and Disability: A Randomized Controlled Trial.

    Science.gov (United States)

    Ayhan, Hatice; Tastan, Sevinc; Iyigün, Emine; Oztürk, Erkan; Yildiz, Ramazan; Görgülü, Semih

    2016-06-01

    Although there are a limited number of studies showing effects of neck stretching exercises following a thyroidectomy in reducing neck discomfort symptoms, no study has specifically dealt with and examined the effect of neck stretching exercises on neck pain and disability. To analyze the effect of neck stretching exercises, following a total thyroidectomy, on reducing neck pain and disability. A randomized controlled trial was conducted. The participants were randomly assigned either to the stretching exercise group (n = 40) or to the control group (n = 40). The stretching exercise group learned the neck stretching exercises immediately after total thyroidectomy. The effects of the stretching exercises on the participants' neck pain and disability, neck sensitivity, pain with neck movements as well as on wound healing, were evaluated at the end of the first week and at 1 month following surgery. When comparing neck pain and disability scale (NPDS) scores, neck sensitivity and pain with neck movement before thyroidectomy, after 1 week and after 1-month time-points, it was found that patients experienced significantly less pain and disability in the stretching exercise group than the control group (p stretching exercise group were significantly lower than those of the control group. However, there was no significant difference between the groups with regard to the scores at the 1-month evaluation (p > .05). Neck stretching exercises done immediately after a total thyroidectomy reduce short-term neck pain and disability symptoms. © 2016 Sigma Theta Tau International.

  16. Unexpected decoupling of stretching and bending modes in protein gels.

    Science.gov (United States)

    Gibaud, Thomas; Zaccone, Alessio; Del Gado, Emanuela; Trappe, Véronique; Schurtenberger, Peter

    2013-02-01

    We show that gels formed by arrested spinodal decomposition of protein solutions exhibit elastic properties in two distinct frequency domains, both elastic moduli exhibiting a remarkably strong dependence on volume fraction. Considering the large difference between the protein size and the characteristic length of the network we model the gels as porous media and show that the high and low frequency elastic moduli can be respectively attributed to stretching and bending modes. The unexpected decoupling of the two modes in the frequency domain is attributed to the length scale involved: while stretching mainly relates to the relative displacement of two particles, bending involves the deformation of a strand with a thickness of the order of a thousand particle diameters.

  17. The Effects of Proprioceptive Neuromuscular Facilitation Stretching on Post-Exercise Delayed Onset Muscle Soreness in Young Adults.

    Science.gov (United States)

    McGRATH, Ryan P; Whitehead, James R; Caine, Dennis J

    Until recently, the scientific community believed that post-exercise stretching could reduce delayed onset muscle soreness (DOMS), but recent reviews of studies on the topic have concluded that pre- or post-exercise static stretching has no effect on mitigating DOMS. However, the effect of proprioceptive neuromuscular facilitation (PNF) post-exercise stretching on preventing DOMS has not been adequately studied. The purpose of this study was to determine the effect of post-exercise PNF stretching on DOMS. Young adult participants (N=57) were randomly assigned to a PNF stretching group (n=19), a static stretching group (n=20), and to a no-stretching control group (n=18). All participants completed exercise designed to induce DOMS prior to post-exercise experimental stretching protocols. Participants rated their soreness level on a pain scale 24 and 48 hours post-exercise. A 3 × 2 mixed ANOVA showed there was an effect for time ( p <.01). Post hoc testing revealed that DOMS pain significantly decreased ( p <.05) from 24 to 48 hours post-exercise for the PNF and control groups, but not for the static stretching group. Other analyses revealed a significant correlation ( r =.61, p <.01) between the pre- and post-exercise stretch scores and the 48 hour post-exercise pain score for the PNF group. Consistent with the results of previous research on post-exercise static stretching, these results indicate that post-exercise PNF stretching also does not prevent DOMS. However, the correlation analysis suggests it is possible the pre-stretch muscle contractions of the post-exercise PNF protocol may have placed a load on an already damaged muscle causing more DOMS for some participants.

  18. The Effects of Proprioceptive Neuromuscular Facilitation Stretching on Post-Exercise Delayed Onset Muscle Soreness in Young Adults

    Science.gov (United States)

    McGRATH, RYAN P.; WHITEHEAD, JAMES R.; CAINE, DENNIS J.

    2014-01-01

    Until recently, the scientific community believed that post-exercise stretching could reduce delayed onset muscle soreness (DOMS), but recent reviews of studies on the topic have concluded that pre- or post-exercise static stretching has no effect on mitigating DOMS. However, the effect of proprioceptive neuromuscular facilitation (PNF) post-exercise stretching on preventing DOMS has not been adequately studied. The purpose of this study was to determine the effect of post-exercise PNF stretching on DOMS. Young adult participants (N=57) were randomly assigned to a PNF stretching group (n=19), a static stretching group (n=20), and to a no-stretching control group (n=18). All participants completed exercise designed to induce DOMS prior to post-exercise experimental stretching protocols. Participants rated their soreness level on a pain scale 24 and 48 hours post-exercise. A 3 × 2 mixed ANOVA showed there was an effect for time (p<.01). Post hoc testing revealed that DOMS pain significantly decreased (p<.05) from 24 to 48 hours post-exercise for the PNF and control groups, but not for the static stretching group. Other analyses revealed a significant correlation (r=.61, p<.01) between the pre- and post-exercise stretch scores and the 48 hour post-exercise pain score for the PNF group. Consistent with the results of previous research on post-exercise static stretching, these results indicate that post-exercise PNF stretching also does not prevent DOMS. However, the correlation analysis suggests it is possible the pre-stretch muscle contractions of the post-exercise PNF protocol may have placed a load on an already damaged muscle causing more DOMS for some participants. PMID:27182398

  19. Comparison of active stretching technique and static stretching technique on hamstring flexibility.

    Science.gov (United States)

    Meroni, Roberto; Cerri, Cesare Giuseppe; Lanzarini, Carlo; Barindelli, Guido; Morte, Giancesare Della; Gessaga, Viviana; Cesana, Gian Carlo; De Vito, Giovanni

    2010-01-01

    To compare a passive and an active stretching technique to determine which one would produce and maintain the greatest gain in hamstring flexibility. To determine whether a passive or an active stretching technique results in a greater increase in hamstring flexibility and to compare whether the gains are maintained. Randomized controlled trial. Institutional. Sixty-five volunteer healthy subjects completed the enrollment questionnaire, 33 completed the required 75% of the treatment after 6 weeks, and 22 were assessed 4 weeks after the training interruption. A 6-week stretching program with subjects divided into 2 groups with group 1 performing active stretching exercises and group 2 performing passive stretching exercises. Range of motion (ROM) was measured after 3 and 6 weeks of training and again 4 weeks after the cessation of training and compared with the initial measurement. After 3 weeks of training, the mean gain in group 1 (active stretching) on performing the active knee extension range of motion (AKER) test was 5.7 degrees, whereas the mean gain in group 2 (passive stretching) was 3 degrees (P = .015). After 6 weeks of training, the mean gain in group 1 was 8.7 degrees , whereas the mean gain in group 2 was 5.3 degrees (P = .006). Twenty-two subjects were reassessed 4 weeks after the cessation of the training with the maintained gain of ROM in group 1 being 6.3 degrees , whereas the maintained gain in group 2 was 0.1 degrees (P = .003). Active stretching produced the greater gain in the AKER test, and the gain was almost completely maintained 4 weeks after the end of the training, which was not seen with the passive stretching group. Active stretching was more time efficient compared with the static stretching and needed a lower compliance to produce effects on flexibility.

  20. Linear viscoelastic characterization from filament stretching rheometry

    DEFF Research Database (Denmark)

    Wingstrand, Sara Lindeblad; Alvarez, Nicolas J.; Hassager, Ole

    Traditionally, linear viscoelasticity is measured using small amplitude oscillatory shear flow. Due to experimental difficulties, shear flows are predominately confined to the linear and mildly nonlinear regime. On the other hand, extensional flows have proven more practical in measuring viscoela......Traditionally, linear viscoelasticity is measured using small amplitude oscillatory shear flow. Due to experimental difficulties, shear flows are predominately confined to the linear and mildly nonlinear regime. On the other hand, extensional flows have proven more practical in measuring...... viscoelasticity well into the nonlinear regime. Therefore at present, complete rheological characterization of a material requires two apparatuses: a shear and an extensional rheometer. This work is focused on developing a linear viscoelastic protocol for the filament stretching rheometer (FSR) in order...... to measure both linear and nonlinear dynamics on a single apparatus. With a software modification to the FSR motor control, we show that linear viscoelasticity can be measured via small amplitude squeeze flow (SASF). Squeeze flow is a combination of both shear and extensional flow applied by axially...

  1. Anomalies in the coil-stretch transition of flexible polymers

    Science.gov (United States)

    Ghosal, Aishani; Cherayil, Binny J.

    2018-03-01

    The flow-induced coil-stretch transition of high molecular weight polymers has generally been held to be of first order. But evidence of significant slowing down in the rate at which the polymers relax to equilibrium in the vicinity of the transition suggests that the thermodynamic character of the transition may be less clear-cut. The above slowing down effect is actually characteristic of a second-order transition, and it points to the existence of a broad spectrum of conformational states in the transition region, analogous to the existence of fluctuations of all length scales at a critical point. In this paper, using a path integral approach based on a free-draining finitely extensible chain model, we calculate various polymer properties as a function of elongational flow as a way of exploring different statistical mechanical details of the coil-stretch transition. These properties include the molecular weight dependence of the flow-extension curve of the polymer, the distribution of its steady-state end-to-end distances, and the characteristic relaxation time τR of these distances. Among other findings, our calculations indicate that the coil-stretch transition is discontinuous in the N → ∞ limit, that the effective free energy of the chain is unimodal at all values of the flow, becoming broad and flat in the immediate vicinity of the transition, and that the ratio of τR to the Rouse relaxation time increases abruptly at the transition before eventually reaching a plateau value at large flow strengths. These aspects of the coil-stretch transition place it among a larger class of unconventional nominally first-order single chain transitions that include the adsorption transition of surface-tethered polymers and the escape transition of compressed polymers.

  2. Ultrastructural immunocytochemistry for the central region of keratin associated-beta-proteins (beta-keratins) shows the epitope is constantly expressed in reptilian epidermis.

    Science.gov (United States)

    Alibardi, L

    2013-08-01

    The presence of beta-proteins containing a core-box region in specific regions of reptilian epidermis has been studied by immunological methods. Alpha-keratins are detected by the antibody AK2 that recognizes a sequence toward the C-terminal of acidic alpha-keratins of 48-52kDa. Beta-proteins are recognized by an antibody directed to the core-box region specific for these proteins of 18-37kDa. The AK2 antibody labels with variable intensity alpha-keratin bundles in basal and suprabasal keratinocytes in the epidermis of representative species of reptiles but immunolabeling decreases or disappears in pre-corneous and corneous cells. As opposite, the core-box antibody only labels with variable intensity the dense beta-corneous material formed in pre-corneous and corneous layers of crocodilian and turtle epidermis. In lepidosaurian epidermis the core-box antibody labels the beta-layer while the mesos and alpha-layers are poorly or not labeled. The immunological evidence indicates that beta-proteins are synthesized in the upper spinosus and pre-corneous layers of the epidermis and replace or mask the initial alpha-keratin framework present in keratinocytes as they differentiate into cells of the beta-layer. In the specialized pad lamellae of gecko and anoline lizards charged beta-proteins accumulate in the adhesive setae and may affect the mechanism of adhesion that allows these lizards to walk vertical surfaces. The addition of beta-proteins to the alpha-keratins in upper cell layers of the epidermis recalls the process of cornification of mammalian epidermis where specific keratin-associated proteins (involucrin, loricrin and filaggrin) associate with the keratin framework in terminally differentiating keratinocytes of the stratum corneum. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. The purinergic component of human bladder smooth muscle cells’ proliferation and contraction under physiological stretch

    Energy Technology Data Exchange (ETDEWEB)

    Wazir, Romel; Luo, De-Yi; Tian, Ye; Yue, Xuan; Li, Hong; Wang, Kun-Jie, E-mail: kunjiewangatscu@163.com

    2013-07-26

    Highlights: •Stretch induces proliferation and contraction. •Optimum applied stretch in vitro is 5% and 10% equibiaxial stretching respectively. •Expression of P2X1 and P2X2 is upregulated after application of stretch. •P2X2 is possibly more susceptible to stretch related changes. •Purinoceptors functioning may explain conditions with atropine resistance. -- Abstract: Objective: To investigate whether cyclic stretch induces proliferation and contraction of human smooth muscle cells (HBSMCs), mediated by P2X purinoceptor 1 and 2 and the signal transduction mechanisms of this process. Methods: HBSMCs were seeded on silicone membrane and stretched under varying parameters; (equibiaxial elongation: 2.5%, 5%, 10%, 15%, 20%, 25%), (Frequency: 0.05 Hz, 0.1 Hz, 0.2 Hz, 0.5 Hz, 1 Hz). 5-Bromo-2-deoxyuridine assay was employed for proliferative studies. Contractility of the cells was determined using collagen gel contraction assay. After optimal physiological stretch was established; P2X1 and P2X2 were analyzed by real time polymerase chain reaction and Western Blot. Specificity of purinoceptors was maintained by employing specific inhibitors; (NF023 for P2X1, and A317491for P2X2), in some experiments. Results: Optimum proliferation and contractility were observed at 5% and 10% equibiaxial stretching respectively, applied at a frequency of 0.1 Hz; At 5% stretch, proliferation increased from 0.837 ± 0.026 (control) to 1.462 ± 0.023%, p < 0.05. Mean contraction at 10% stretching increased from 31.7 ± 2.3%, (control) to 78.28 ±1.45%, p < 0.05. Expression of P2X1 and P2X2 was upregulated after application of stretch. Inhibition had effects on proliferation (1.232 ± 0.051, p < 0.05 NF023) and (1.302 ± 0.021, p < 0.05 A314791) while contractility was markedly reduced (68.24 ± 2.31, p < 0.05 NF023) and (73.2 ± 2.87, p < 0.05 A314791). These findings shows that mechanical stretch can promote magnitude-dependent proliferative and contractile modulation of HBSMCs in

  4. How to determine local stretching and tension in a flow-stretched DNA molecule

    DEFF Research Database (Denmark)

    Pedersen, Jonas Nyvold; Marie, Rodolphe; Kristensen, Anders

    2016-01-01

    We determine the nonuniform stretching of and tension in amega base pairs-long fragment of deoxyribonucleic acid (DNA) that is flow stretched in a nanofluidic chip. We use no markers, do not know the contour length of the DNA, and do not have the full DNA molecule inside our field of view. Instead...

  5. The Comparative Study of the Effect of Stabilization Exercise and Stretching-Strengthening Exercise on Balance Parameters in Forward Head Posture Patients

    Directory of Open Access Journals (Sweden)

    Solmaz Salehi

    2013-04-01

    Full Text Available Objective: Balance disturbance is one of the observed impairments in patient with forward head posture (FHP. The aim of this study was comparing the effect of stabilization and stretching-strengthening exercises on the improvement of balance in these patients. Materials & Methods: Thirty three females with FHP were randomized into three groups of stabilization training, stretching-strengthening and control. The degree of FHP was measured using plumb line and the crania-vertebral angle. Balance tests performed in three different standing conditions on a force platform. The subjects were evaluated after 6 weeks training and 1 month follow-up by repeated measure ANOVA and T-test through SPSS software. Results: Balance parameters in both stretching-strengthening and control groups showed no significant changes (P>0.05 while in the stabilization group, significant decrease in displacement and velocity of center of pressure were seen under conditions of double-leg, eyes-open, foam-surface and single-leg, eyes-closed, rigid-surface (P0.05. Conclusion: In the conditions of standing that visual and proprioception information from plantar region of foot is challenged, stabilization exercises lead to more balance improvement than stretching-strengthening exercises.

  6. Retinal glial (Müller ) cells: sensing and responding to tissue stretch.

    Science.gov (United States)

    Lindqvist, Niclas; Liu, Qing; Zajadacz, Joachim; Franze, Kristian; Reichenbach, Andreas

    2010-03-01

    To test whether Müller glial cells sense, and respond to, mechanical tension in the retina. A device was designed to stretch the retina at right angles to its surface, across retinal layers. Pieces of retina were mounted between two hollow tubes, and uniaxial force was applied to the tissue using a micrometer-stepping motor. Müller cells were selectively stained with the fluorescent, calcium-sensitive dye X-Rhod-1 and were monitored in real time during retinal stretch in vitro. Immunohistochemistry was used to study protein levels and activation of intracellular pathways in stretched retinas. Müller cells responded acutely with transient increases in fluorescence during stretch, indicative of increased intracellular calcium levels. All the Müller cells elongated uniformly, and there was no apparent difference between retinal layers in resistance against mechanical deformation. After stretch, Müller cells showed fast activation of extracellular signal-regulated kinase (after 15 minutes), upregulation of transcription factor c-Fos (after 1 hour), and basic fibroblast growth factor (after 3 hours). No changes in intermediate filament protein expression were observed in Müller cells up to 3 hours after stretch. A novel technique was developed for real-time monitoring of Müller cells during retinal stretch, which allowed the identification of Müller cells as a mechanoresponsive cell type. Mechanical stress triggers molecular responses in Müller cells that could prevent retinal damage.

  7. A comparison of two stretching programs for hamstring muscles: A randomized controlled assessor-blinded study.

    Science.gov (United States)

    Demoulin, Christophe; Wolfs, Sébastien; Chevalier, Madeline; Granado, Caroline; Grosdent, Stéphanie; Depas, Yannick; Roussel, Nathalie; Hage, Renaud; Vanderthommen, Marc

    2016-01-01

    Most parameters regarding hamstring flexibility training programs have been investigated; however, the joint (i.e. hip or knee) on which the stretching should preferentially be focused needs to be further explored. This randomized controlled assessor-blinded study aimed to investigate the influence of this parameter. We randomly assigned 111 asymptomatic participants with tight hamstring muscles in three groups: a control group and two groups following a different home-based 8-week (five 10-minute sessions per week) hamstring stretching program (i.e. stretching performed by flexing the hip while keeping the knee extended [SH] or by first flexing the hip with a flexed knee and then extending the knee [SK]). Range of motion (ROM) of hip flexion and knee extension were measured before and after the stretching program by means of the straight leg raising test and the passive knee extension angle test, respectively. Eighty-nine participants completed the study. A significant increase in ROM was observed at post-test. Analyses showed significant group-by-time interactions for changes regarding all outcomes. Whereas the increase in hip flexion and knee extension ROM was higher in the stretching groups than in the CG (especially for the SH group p 0.05). In conclusion, the fact that both stretching programs resulted in similar results suggests no influence of the joint at which the stretching is focused upon, as assessed by the straight leg raising and knee extension angle tests.

  8. CURRENT CONCEPTS IN MUSCLE STRETCHING FOR EXERCISE AND REHABILITATION

    Science.gov (United States)

    2012-01-01

    Stretching is a common activity used by athletes, older adults, rehabilitation patients, and anyone participating in a fitness program. While the benefits of stretching are known, controversy remains about the best type of stretching for a particular goal or outcome. The purpose of this clinical commentary is to discuss the current concepts of muscle stretching interventions and summarize the evidence related to stretching as used in both exercise and rehabilitation. PMID:22319684

  9. CURRENT CONCEPTS IN MUSCLE STRETCHING FOR EXERCISE AND REHABILITATION

    OpenAIRE

    Page, Phil

    2012-01-01

    Stretching is a common activity used by athletes, older adults, rehabilitation patients, and anyone participating in a fitness program. While the benefits of stretching are known, controversy remains about the best type of stretching for a particular goal or outcome. The purpose of this clinical commentary is to discuss the current concepts of muscle stretching interventions and summarize the evidence related to stretching as used in both exercise and rehabilitation.

  10. Summary of the stretching tectonics research

    International Nuclear Information System (INIS)

    Yu Dagan

    1994-01-01

    The rise of stretching tectonics is established on the basis of recent structural geology theory, the establishment of metamorphic nucleus complex structural model on one hand plays an important promoting art to the development of stretching structure, on the other hand, it needs constant supplement and perfection in practice. Metamorphic nucleus complex is the carrier of comparatively deep geological information in vertical section of the crust and has wide distribution in the era of south China. Evidently, it can be taken as the 'key' to understanding the deep and studying the basement, Strengthening the study will play the important promoting role to the deep prospecting. The study of stretching tectonics is not only limited within the range of structure and metamorphism, but combine with the studies of sedimentation, magmatism, metamorphism and mineralization, thus form a new field of tectonic geology of self-developing system

  11. Optofluidic time-stretch microscopy: recent advances

    Science.gov (United States)

    Lei, Cheng; Nitta, Nao; Ozeki, Yasuyuki; Goda, Keisuke

    2018-04-01

    Flow cytometry is an indispensable method for valuable applications in numerous fields such as immunology, pathology, pharmacology, molecular biology, and marine biology. Optofluidic time-stretch microscopy is superior to conventional flow cytometry methods for its capability to acquire high-quality images of single cells at a high-throughput exceeding 10,000 cells per second. This makes it possible to extract copious information from cellular images for accurate cell detection and analysis with the assistance of machine learning. Optofluidic time-stretch microscopy has proven its effectivity in various applications, including microalga-based biofuel production, evaluation of thrombotic disorders, as well as drug screening and discovery. In this review, we discuss the principles and recent advances of optofluidic time-stretch microscopy.

  12. Optofluidic time-stretch quantitative phase microscopy.

    Science.gov (United States)

    Guo, Baoshan; Lei, Cheng; Wu, Yi; Kobayashi, Hirofumi; Ito, Takuro; Yalikun, Yaxiaer; Lee, Sangwook; Isozaki, Akihiro; Li, Ming; Jiang, Yiyue; Yasumoto, Atsushi; Di Carlo, Dino; Tanaka, Yo; Yatomi, Yutaka; Ozeki, Yasuyuki; Goda, Keisuke

    2018-03-01

    Innovations in optical microscopy have opened new windows onto scientific research, industrial quality control, and medical practice over the last few decades. One of such innovations is optofluidic time-stretch quantitative phase microscopy - an emerging method for high-throughput quantitative phase imaging that builds on the interference between temporally stretched signal and reference pulses by using dispersive properties of light in both spatial and temporal domains in an interferometric configuration on a microfluidic platform. It achieves the continuous acquisition of both intensity and phase images with a high throughput of more than 10,000 particles or cells per second by overcoming speed limitations that exist in conventional quantitative phase imaging methods. Applications enabled by such capabilities are versatile and include characterization of cancer cells and microalgal cultures. In this paper, we review the principles and applications of optofluidic time-stretch quantitative phase microscopy and discuss its future perspective. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Molecular orientation behavior of isotactic polypropylene under uniaxial stretching by rheo-Raman spectroscopy

    Directory of Open Access Journals (Sweden)

    T. Kida

    2016-08-01

    Full Text Available The molecular orientation behavior of isotactic polypropylene (iPP is investigated by using in situ Raman spectroscopy under tensile tests. A versatile method of the tilt-angle correction for the orientation parameters is newly developed, where the molecular orientation in highly oriented specimens is assumed to be entropically favorable. The real-time changes of orientation parameters and orientation distribution functions are determined for the molecular chain axis of iPP during uniaxial stretching. The molecular orientation remains random in the elastic region, and increases after the first yield point. In the yielding region, a broad distribution of orientation toward an intermediate angle of 30–70° from the stretching direction is observed. This is interpreted as reorientation of the crystalline chains being hindered by rigid, bulky lamellar cluster units. After the yielding region, orientation toward the stretching direction proceeds rapidly, approaching highly oriented states.

  14. Acute Effect of Different Combined Stretching Methods on Acceleration and Speed in Soccer Players

    Directory of Open Access Journals (Sweden)

    Amiri-Khorasani Mohammadtaghi

    2016-04-01

    Full Text Available The purpose of this study was to investigate the acute effect of different stretching methods, during a warm-up, on the acceleration and speed of soccer players. The acceleration performance of 20 collegiate soccer players (body height: 177.25 ± 5.31 cm; body mass: 65.10 ± 5.62 kg; age: 16.85 ± 0.87 years; BMI: 20.70 ± 5.54; experience: 8.46 ± 1.49 years was evaluated after different warm-up procedures, using 10 and 20 m tests. Subjects performed five types of a warm-up: static, dynamic, combined static + dynamic, combined dynamic + static, and no-stretching. Subjects were divided into five groups. Each group performed five different warm-up protocols in five non-consecutive days. The warm-up protocol used for each group was randomly assigned. The protocols consisted of 4 min jogging, a 1 min stretching program (except for the no-stretching protocol, and 2 min rest periods, followed by the 10 and 20 m sprint test, on the same day. The current findings showed significant differences in the 10 and 20 m tests after dynamic stretching compared with static, combined, and no-stretching protocols. There were also significant differences between the combined stretching compared with static and no-stretching protocols. We concluded that soccer players performed better with respect to acceleration and speed, after dynamic and combined stretching, as they were able to produce more force for a faster execution.

  15. Flow of nanofluid by nonlinear stretching velocity

    Science.gov (United States)

    Hayat, Tasawar; Rashid, Madiha; Alsaedi, Ahmed; Ahmad, Bashir

    2018-03-01

    Main objective in this article is to model and analyze the nanofluid flow induced by curved surface with nonlinear stretching velocity. Nanofluid comprises water and silver. Governing problem is solved by using homotopy analysis method (HAM). Induced magnetic field for low magnetic Reynolds number is not entertained. Development of convergent series solutions for velocity and skin friction coefficient is successfully made. Pressure in the boundary layer flow by curved stretching surface cannot be ignored. It is found that magnitude of power-law index parameter increases for pressure distibutions. Magnitude of radius of curvature reduces for pressure field while opposite trend can be observed for velocity.

  16. Lattice stretching bistability and dynamic heterogeneity

    DEFF Research Database (Denmark)

    Christiansen, Peter Leth; Savin, A. V.; Zolotaryuk, A. V.

    2012-01-01

    A simple one-dimensional lattice model is suggested to describe the experimentally observed plateau in force-stretching diagrams for some macromolecules. This chain model involves the nearest-neighbor interaction of a Morse-like potential (required to have a saturation branch) and a harmonic second......-neighbor coupling. Under an external stretching applied to the chain ends, the intersite Morse-like potential results in the appearance of a double-well potential within each chain monomer, whereas the interaction between the second neighbors provides a homogeneous bistable (degenerate) ground state, at least...

  17. Stretching and folding mechanism in foams

    Energy Technology Data Exchange (ETDEWEB)

    Tufaile, Alberto [Escola de Artes, Ciencias e Humanidades, Soft Matter Laboratory, Universidade de Sao Paulo, 03828-000 Sao Paulo, SP (Brazil)], E-mail: tufaile@usp.br; Pedrosa Biscaia Tufaile, Adriana [Escola de Artes, Ciencias e Humanidades, Soft Matter Laboratory, Universidade de Sao Paulo, 03828-000 Sao Paulo, SP (Brazil)

    2008-10-13

    We have described the stretching and folding of foams in a vertical Hele-Shaw cell containing air and a surfactant solution, from a sequence of upside-down flips. Besides the fractal dimension of the foam, we have observed the logistic growth for the soap film length. The stretching and folding mechanism is present during the foam formation, and this mechanism is observed even after the foam has reached its respective maximum fractal dimension. Observing the motion of bubbles inside the foam, large bubbles present power spectrum associated with random walk motion in both directions, while the small bubbles are scattered like balls in a Galton board.

  18. Anomalous thermal response of silicene to uniaxial stretching

    Science.gov (United States)

    Hu, Ming; Zhang, Xiaoliang; Poulikakos, Dimos

    2013-05-01

    Silicene—the silicon counterpart of graphene—has a two-dimensional structure that leads to a host of interesting physical and chemical properties of significant utility. We report here an investigation with nonequilibrium molecular dynamics simulations of thermal transport in a single-layer silicene sheet under uniaxial stretching. We discovered that, contrary to its counterpart of graphene and despite the similarity of their honeycomb lattice structure, silicene exhibits an anomalous thermal response to tensile strain: The thermal conductivity of silicene and silicene nanoribbons first increases significantly with applied tensile strain rather than decreasing and then fluctuates at an elevated plateau. By quantifying the relative contribution from different phonon polarizations, we show first that the phonon transport in silicene is dominated by the out-of-plane flexural modes, similar to graphene. We attribute subsequently the unexpected and markedly different behavior of silicene to the interplay between two competing mechanisms governing heat conduction in a stretched silicene sheet, namely, (1) uniaxial stretching modulation in the longitudinal direction significantly depressing the phonon group velocities of longitudinal and transverse modes (phonon softening) and hindering heat conduction, and (2) phonon stiffening in the flexural modes counteracting the phonon softening effect and facilitating thermal transport. The abnormal behavior of the silicene sheet is further correlated to the unique deformation characteristics of its hexagonal lattice. Our study offers perspectives of modulating the thermal properties of low-dimensional structures for applications such as thermoelectric, photovoltaic, and optoelectronic devices.

  19. Genetic stretching factors in masseter muscle after orthognathic surgery.

    Science.gov (United States)

    Breuel, Wiebke; Krause, Micaela; Schneider, Matthias; Harzer, Winfried

    2013-09-01

    Up to 30% of patients relapse after orthognathic operations, and one reason might be incomplete neuromuscular adaptation of the masticatory muscles. Displacement of the mandible in sagittal or vertical directions, or both, leads to stretching or compression of these muscles. The aim of this study was to analyse stretching factors in 35 patients with retrognathism or prognathism of the mandible (Classes II and III). Tissue samples were taken from both sides of the masseter muscle (anterior and posterior) both before and 6 months after operation. Developmental myosin heavy chains MYH3 and MYH8, the fast and slow MYH 1, 2, and 7, and cyclo-oxygenase (COX) 2, forkhead transcription factor (FOX)O3a, calcineurin, and nuclear factor of activated T cells (NFAT)1c (stretching and regeneration-specific), were analysed by real time polymerase chain reaction (PCR). Correlations of Class II and III with sagittal and vertical cephalometric measurements ANB and ML-NL-angle were examined, and the results showed significant differences in amounts of MYH8 (pstretching indicators FOXO3a, calcineurin, and NFAT1c only in Class II patients. This means that stretching of the masseter muscle caused by lengthening of the mandible and raising of the bite in Class II patients was more likely to lead to relapse (similar to that in patients with open bite) than in Class III patients. In conclusion, deep bite should be reduced more by incisor intrusion than by skeletal opening. The focus in these patients should be directed towards physiotherapeutic strengthening of the muscles of mastication, and more consideration should be given to change in the vertical dimension. Copyright © 2012 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  20. Stretch-induced intussuceptive and sprouting angiogenesis in the chick chorioallantoic membrane.

    Science.gov (United States)

    Belle, Janeil; Ysasi, Alexandra; Bennett, Robert D; Filipovic, Nenad; Nejad, Mohammad Imani; Trumper, David L; Ackermann, Maximilian; Wagner, Willi; Tsuda, Akira; Konerding, Moritz A; Mentzer, Steven J

    2014-09-01

    Vascular systems grow and remodel in response to not only metabolic needs, but also mechanical influences as well. Here, we investigated the influence of tissue-level mechanical forces on the patterning and structure of the chick chorioallantoic membrane (CAM) microcirculation. A dipole stretch field was applied to the CAM using custom computer-controlled servomotors. The topography of the stretch field was mapped using finite element models. After 3days of stretch, Sholl analysis of the CAM demonstrated a 7-fold increase in conducting vessel intersections within the stretch field (p0.05). In contrast, corrosion casting and SEM of the stretch field capillary meshwork demonstrated intense sprouting and intussusceptive angiogenesis. Both planar surface area (p<0.05) and pillar density (p<0.01) were significantly increased relative to control regions of the CAM. We conclude that a uniaxial stretch field stimulates the axial growth and realignment of conducting vessels as well as intussusceptive and sprouting angiogenesis within the gas exchange capillaries of the ex ovo CAM. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Stretch-induced Intussuceptive and Sprouting Angiogenesis in the Chick Chorioallantoic Membrane

    Science.gov (United States)

    Belle, Janeil; Ysasi, Alexandra; Bennett, Robert; Filipovic, Nenad; Nejad, Mohammad Imani; Trumper, David L.; Ackermann, Max; Wagner, Willi; Tsuda, Akira; Konerding, Moritz A.; Mentzer, Steven J.

    2014-01-01

    Vascular systems grow and remodel in response to not only metabolic needs, but mechanical influences as well. Here, we investigated the influence of tissue-level mechanical forces on the patterning and structure of the chick chorioallantoic membrane (CAM) microcirculation. A dipole stretch field was applied to the CAM using custom computer-controlled servomotors. The topography of the stretch field was mapped using finite element models. After 3 days of stretch, Sholl analysis of the CAM demonstrated a 7-fold increase in conducting vessel intersections within the stretch field (p0.05). In contrast, corrosion casting and SEM of the stretch field capillary meshwork demonstrated intense sprouting and intussusceptive angiogenesis. Both planar surface area (p<0.05) and pillar density (p<0.01) were significantly increased relative to control regions of the CAM. We conclude that a uniaxial stretch field stimulates the axial growth and realignment of conducting vessels as well as intussusceptive and sprouting angiogenesis within the gas exchange capillaries of the ex ovo CAM. PMID:24984292

  2. Immediate effects of quantified hamstring stretching: hold-relax proprioceptive neuromuscular facilitation versus static stretching.

    Science.gov (United States)

    Puentedura, Emilio J; Huijbregts, Peter A; Celeste, Shelley; Edwards, Dale; In, Alastair; Landers, Merrill R; Fernandez-de-Las-Penas, Cesar

    2011-08-01

    To compare the immediate effects of a hold-relax proprioceptive neuromuscular facilitation stretching (HR-PNF) versus static stretch (SS) on hamstring flexibility in healthy, asymptomatic subjects. Thirty subjects (13 female; mean age 25.7 ± 3.0, range 22-37) without excessive hamstring muscle flexibility were randomly assigned to one of two stretch groups: HR-PNF or SS. The left leg was treated as a control and did not receive any intervention. The right leg was measured for ROM pre- and post-stretch interventions, with subjects receiving randomly assigned interventions one week apart. Data were analyzed with a 3 (intervention: HR-PNF, SS, control) × 2 (time: pre and post) factorial ANOVA with repeated measures and appropriate post-hoc analyses. A significant interaction was observed between intervention and time for hamstring extensibility, F(2,58) = 25.229, p < .0005. Main effect of intervention for the tested leg was not significant, p = .782 indicating that there was no difference between the two stretch conditions. However, main effect for time was significant (p < .0005), suggesting that hamstring extensibility (for both stretching conditions) after intervention was greater than before. No significant differences were found when comparing the effectiveness of HR-PNF and SS techniques. Both stretching methods resulted in significant immediate increases in hamstring length. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. One minute static stretch of plantar flexors transiently increases H reflex excitability and exerts no effect on corticospinal pathways.

    Science.gov (United States)

    Budini, Francesco; Gallasch, Eugen; Christova, Monica; Rafolt, Dietmar; Rauscher, Andreas Benedikt; Tilp, Markus

    2017-08-01

    What is the central question of this study? What mediates neural responses following static stretching, and how long do these influences last? What is the main finding and its importance? This study shows that 1 min of static stretching inhibits the tendon tap reflex and facilitates the H reflex without influencing motor-evoked potentials. The results indicate that at least two different mechanisms mediate neural responses after static stretching. The purpose of this study was to determine whether the neural responses observed after static stretching are mediated by sensitivity of muscle spindles, spinal excitability or cortical excitability and how long these influences last. Nineteen volunteers (25.7 ± 5.6 years old) were tested for the tendon tap reflex (T-reflex), H reflex and motor-evoked potentials on ankle flexors and extensors immediately, 5 and 10 min after 1 min static stretching applied at individual maximal ankle dorsiflexion, as well as immediately, 5 and 10 min after a control period of the same duration. Comparison of measurements collected immediately after stretching or control conditions revealed that the T-reflex was weaker after stretching than after control (-59.2% P = 0.000). The T-reflex showed a slow recovery rate within the first 150 s after stretching, but 5 min after the inhibition had disappeared. The H reflex increased immediately after stretching (+18.3%, P = 0.036), showed a quick tendency to recover and returned to control values within 5 min from stretching. Motor-evoked potentials were not affected by the procedure. These results suggest that 1 min of static stretching primarily decreases muscle spindle sensitivity and facilitates the H reflex, whereas effects on the motor cortex can be excluded. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

  4. Effectiveness of passive stretching versus hold relax technique in flexibility of hamstring muscle

    Directory of Open Access Journals (Sweden)

    Gauri Shankar

    2010-10-01

    Full Text Available Aim: To compare the effectiveness of passive stretching and hold relax technique in the flexibility of hamstring muscle. Methods: A total of 80 normal healthy female subjects between age group 20-30 years referred to the department of physiotherapy, Sumandeep Vidyapeeth University, sampling method being convenient sampling. The subjects were randomly divided in two groups i.e. passive stretching group (n=40 and PNF group (n=40 and given passive stretching and proprioceptive neuromuscular facilitation technique respectively. Active knee extension range was measured before and after the intervention by goniometer. Results: t test showed a highly significant (p=0.000 increase in range of motion in PNF group. Conclusion: Proprioceptive neuromuscular facilitation technique is more effective in increasing hamstring flexibility than the passive stretching.

  5. Realistic searches on stretched exponential networks

    Indian Academy of Sciences (India)

    Vol. 71, No. 2. — journal of. August 2008 physics pp. 313–317. Realistic searches on stretched exponential networks. PARONGAMA SEN. Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road,. Kolkata 700 009, India .... [4] S Milgram, Psychology Today 1, 60 (1967). J Travers and S Milgram, ...

  6. Filament stretching rheometry of polymer melts

    DEFF Research Database (Denmark)

    Hassager, Ole; Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz

    2005-01-01

    The Filament Stretching Rheometry (FSR) method developed by Sridhar, McKinley and coworkers for polymer solutions has been extended to be used also for polymer melts. The design of a melt-FSR will be described and differences to conventional melt elongational rheometers will be pointed out. Results...

  7. Cloud Network Helps Stretch IT Dollars

    Science.gov (United States)

    Collins, Hilton

    2012-01-01

    No matter how many car washes or bake sales schools host to raise money, adding funds to their coffers is a recurring problem. This perpetual financial difficulty makes expansive technology purchases or changes seem like a pipe dream for school CIOs and has education technologists searching for ways to stretch money. In 2005, state K-12 school…

  8. The stretch zone of automotive steel sheets

    Indian Academy of Sciences (India)

    on steel grade, on the rolling direction as well as on the loading rate. Stretch zones ... This interaction is demonstrated at a fracture surface as a bounded transition between initiatory crack (e.g., fatigue) and either ... The materials examined in this study are three grades of thin automotive steel sheets: XSG,. HR 45 and DP.

  9. Fractional behaviour at cyclic stretch-bending

    NARCIS (Netherlands)

    Emmens, W.C.; van den Boogaard, Antonius H.; Kazantzis, A.V.; de Hosson, J.Th.M.; Kolleck, R

    2010-01-01

    The fractional behaviour at cyclic stretch-bending has been studied by performing tensile tests at long specimens that are cyclically bent at the same time, on mild steel, dual-phase steel, stainless steel, aluminium and brass. Several types of fracture are observed, these are discussed, as are the

  10. Uninvolved versus target muscle contraction during contract: relax proprioceptive neuromuscular facilitation stretching.

    Science.gov (United States)

    Azevedo, Daniel Camara; Melo, Raphael Marques; Alves Corrêa, Ricardo Vidal; Chalmers, Gordon

    2011-08-01

    The purpose of this study was to compare the acute effect of the contract-relax (CR) stretching technique on knee active range of motion (ROM) using target muscle contraction or an uninvolved muscle contraction. pre-test post-test control experimental design. Clinical research laboratory. Sixty healthy men were randomly assigned to one of three groups. The Contract-Relax group (CR) performed a traditional hamstring CR stretch, the Modified Contract-Relax group (MCR) performed hamstring CR stretching using contraction of an uninvolved muscle distant from the target muscle, and the Control group (CG) did not stretch. Active knee extension test was performed before and after the stretching procedure. Two-way between-within analysis of variance (ANOVA) results showed a significant interaction between group and pre-test to post-test (p < 0.001). Post-hoc examination of individual groups showed no significant change in ROM for the CG (0.8°, p = 0.084), and a significant moderate increase in ROM for both the CR (7.0°, p < 0.001) and MCR (7.0°, p < 0.001) groups. ROM gain following a CR PNF procedure is the same whether the target stretching muscle is contracted, or an uninvolved muscle is contracted. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Effect of single bout versus repeated bouts of stretching on muscle recovery following eccentric exercise.

    Science.gov (United States)

    Torres, Rui; Pinho, Francisco; Duarte, José Alberto; Cabri, Jan M H

    2013-11-01

    To analyze the effects of a single bout and repeated bouts of stretching on indirect markers of exercise-induced muscle damage. A randomized controlled clinical trial at a university human research laboratory was conducted. Fifty-six untrained males were randomly divided into four groups. (I) a single stretching group underwent a single bout of stretching on the quadriceps muscle; (II) an eccentric exercised group underwent eccentric quadriceps muscle contractions until exhaustion; (III) an eccentric exercise group followed by a single bout of stretching; (IV) an eccentric exercised group submitted to repeated bouts of stretching performed immediately and 24, 48, and 72 h post-exercise. Muscle stiffness, muscle soreness, maximal concentric peak torque, and plasma creatine kinase activity were assessed before exercise and 1, 24, 48, 72, and 96 h post-exercise. All exercised groups showed significant reduction in maximal concentric peak torque and significant increases in muscle soreness, muscle stiffness, and plasma creatine kinase. There were no differences between these groups in all assessed variables, with the exception of markers of muscle stiffness, which were significantly lower in the eccentric exercise group followed by single or repeated bouts. The single stretching group showed no change in any assessed variables during the measurement period. Muscle stretching performed after exercise, either as single bout or as repeated bouts, does not influence the levels of the main markers of exercise-induced muscle damage; however, repeated bouts of stretching performed during the days following exercise may have favorable effects on muscle stiffness. Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  12. Effect of passive stretching on the immobilized soleus muscle fiber morphology

    Directory of Open Access Journals (Sweden)

    Coutinho E.L.

    2004-01-01

    Full Text Available The aim of the present study was to determine the effect of stretching applied every 3 days to the soleus muscle immobilized in the shortened position on muscle fiber morphology. Eighteen 16-week-old Wistar rats were used and divided into three groups of 6 animals each: a the left soleus muscle was immobilized in the shortened position for 3 weeks; b during immobilization, the soleus was stretched for 40 min every 3 days; c the non-immobilized soleus was only stretched. Left and right soleus muscles were examined. One portion of the soleus was frozen for histology and muscle fiber area evaluation, while the other portion was used to identify the number and length of serial sarcomeres. Immobilized muscles (group A showed a significant decrease in weight (44 ± 6%, length (19 ± 7%, serial sarcomere number (23 ± 15%, and fiber area (37 ± 31% compared to the contralateral muscles (P < 0.05, paired Student t-test. The immobilized and stretched soleus (group B showed a similar reduction but milder muscle fiber atrophy compared to the only immobilized group (22 ± 40 vs 37 ± 31%, respectively; P < 0.001, ANOVA test. Muscles submitted only to stretching (group C significantly increased the length (5 ± 2%, serial sarcomere number (4 ± 4%, and fiber area (16 ± 44% compared to the contralateral muscles (P < 0.05, paired Student t-test. In conclusion, stretching applied every 3 days to immobilized muscles did not prevent the muscle shortening, but reduced muscle atrophy. Stretching sessions induced hypertrophic effects in the control muscles. These results support the use of muscle stretching in sports and rehabilitation.

  13. EFFECTIVENESS OF PNF STRETCHING AND CYCLIC STRETCHING OF CALF TIGHTNESS ON COLLEGE GOING GIRLS

    Directory of Open Access Journals (Sweden)

    Ashlesha Sirari

    2015-06-01

    Full Text Available Background: Flexibility helps with injury prevention, the reduction of soreness following a workout, and a general sense of well-being. There are different stretching techniques and protocols for improvements in calf extensibility and flexibility. The purpose of the study was to investigate the effectiveness of two techniques i.e. CYCLIC and PNF stretching which improves calf flexibility. This study was done to find the effectiveness of calf Cyclic and PNF stretching technique to improve calf flexibility. Methods: 30 subjects with age group 21-22 years were randomly allocated to 2 groups equally. Group 1(n=15 were given CYCLIC and group 2(n=15 were given PNF stretching technique. Plantar flexion was used to measure the calf tightness which was done before and after the treatment. Treatment was given for 7 days and on the 7th day the calf tightness was again measured. Results: The mean difference of the CYCLIC is 4.6 and mean difference of PNF is 4.7 which indicate that CYCLIC and PNF both are effective to improve calf flexibility but PNF is more effective than CYCLIC to improve calf flexibility. Conclusion: The neurophysiological basis of PNF, stating that the excitatory efficient of the neuromuscular spindle or the inhibitory afferent of the Golgi tendon organ (GTO or both are responsible for the effects. During PNF stretch and isometric contraction of stretched agonists for extended period may cause activation of its neuromuscular spindle. The increase in tension created during the isometric contraction of the pre – lengthened agonist contracts concentrically. Both the fascia & the spindle of the agonist adjust to the nearly lengthened position. These impulses travel via causing post synaptic inhibition of the motor neuron to agonist increasing the tension from the GTO. These impulses can override the impulses coming from the neuromuscular spindles arousing the muscle to reflexly resist to the change in length, thus helping in lengthening

  14. How to Stretch Your Ankle After a Sprain

    Science.gov (United States)

    ... Ankle After A Sprain How to Stretch Your Ankle After A Sprain Page Content You should perform the following stretches ... Consider these home exercises when recuperating from an ankle sprain. Perform them twice per day. While seated, bring ...

  15. Effects of acute static, ballistic, and PNF stretching exercise on the muscle and tendon tissue properties.

    Science.gov (United States)

    Konrad, A; Stafilidis, S; Tilp, M

    2017-10-01

    The purpose of this study was to investigate the influence of a single static, ballistic, or proprioceptive neuromuscular facilitation (PNF) stretching exercise on the various muscle-tendon parameters of the lower leg and to detect possible differences in the effects between the methods. Volunteers (n = 122) were randomly divided into static, ballistic, and PNF stretching groups and a control group. Before and after the 4 × 30 s stretching intervention, we determined the maximum dorsiflexion range of motion (RoM) with the corresponding fascicle length and pennation angle of the gastrocnemius medialis. Passive resistive torque (PRT) and maximum voluntary contraction (MVC) were measured with a dynamometer. Observation of muscle-tendon junction (MTJ) displacement with ultrasound allowed us to determine the length changes in the tendon and muscle, respectively, and hence to calculate stiffness. Although RoM increased (static: +4.3%, ballistic: +4.5%, PNF: +3.5%), PRT (static: -11.4%, ballistic: -11.5%, PNF: -13,7%), muscle stiffness (static: -13.1%, ballistic: -20.3%, PNF: -20.2%), and muscle-tendon stiffness (static: -11.3%, ballistic: -10.5%, PNF: -13.7%) decreased significantly in all the stretching groups. Only in the PNF stretching group, the pennation angle in the stretched position (-4.2%) and plantar flexor MVC (-4.6%) decreased significantly. Multivariate analysis showed no clinically relevant difference between the stretching groups. The increase in RoM and the decrease in PRT and muscle-tendon stiffness could be explained by more compliant muscle tissue following a single static, ballistic, or PNF stretching exercise. © 2017 The Authors Scandinavian Journal of Medicine & Science In Sports Published by John Wiley & Sons Ltd.

  16. Hyperglycemia Augments the Adipogenic Transdifferentiation Potential of Tenocytes and Is Alleviated by Cyclic Mechanical Stretch.

    Science.gov (United States)

    Wu, Yu-Fu; Huang, Yu-Ting; Wang, Hsing-Kuo; Yao, Chung-Chen Jane; Sun, Jui-Sheng; Chao, Yuan-Hung

    2017-12-28

    Diabetes mellitus is associated with damage to tendons, which may result from cellular dysfunction in response to a hyperglycemic environment. Tenocytes express diminished levels of tendon-associated genes under hyperglycemic conditions. In contrast, mechanical stretch enhances tenogenic differentiation. However, whether hyperglycemia increases the non-tenogenic differentiation potential of tenocytes and whether this can be mitigated by mechanical stretch remains elusive. We explored the in vitro effects of high glucose and mechanical stretch on rat primary tenocytes. Specifically, non-tenogenic gene expression, adipogenic potential, cell migration rate, filamentous actin expression, and the activation of signaling pathways were analyzed in tenocytes treated with high glucose, followed by the presence or absence of mechanical stretch. We analyzed tenocyte phenotype in vivo by immunohistochemistry using an STZ (streptozotocin)-induced long-term diabetic mouse model. High glucose-treated tenocytes expressed higher levels of the adipogenic transcription factors PPAR γ and C/EBPs. PPARγ was also highly expressed in diabetic tendons. In addition, increased adipogenic differentiation and decreased cell migration induced by high glucose implicated a fibroblast-to-adipocyte phenotypic change. By applying mechanical stretch to tenocytes in high-glucose conditions, adipogenic differentiation was repressed, while cell motility was enhanced, and fibroblastic morphology and gene expression profiles were strengthened. In part, these effects resulted from a stretch-induced activation of ERK (extracellular signal-regulated kinases) and a concomitant inactivation of Akt. Our results show that mechanical stretch alleviates the augmented adipogenic transdifferentiation potential of high glucose-treated tenocytes and helps maintain their fibroblastic characteristics. The alterations induced by high glucose highlight possible pathological mechanisms for diabetic tendinopathy

  17. Outcome of Specific Piriformis Stretching Technique in Females with Piriformis Syndrome

    Directory of Open Access Journals (Sweden)

    Quratulain Saeed

    2017-10-01

    Full Text Available BACKGROUND: Pain and functional limitation affect the quality of life in piriformis syndrome. Stretching of piriformis is essential in the treatment protocols in physiotherapy, however, which sequence of stretching provides optimal improvement is only determined by trial and error. The purpose of this study was to compare the effects of specific stretching technique in terms of functional outcome in female with piriformis syndrome and to determine the normative length of piriformis at different reference points in females. METHODS: This study was a randomized controlled trial that was conducted in the Physiotherapy Department of the Armed Forces Institute of Rehabilitation Medicine, Rawalpindi, Pakistan between July to December, 2015. This study enrolled 30 patients with piriformis syndrome at outpatient department between the ages of 20 and 50 years. These patients were randomly assigned into two groups. In one group, external rotator sequence of self-stretching (ERS was practiced while in the second group, adductor sequence of passive stretching (APS was performed. Each group was treated for two weeks. Pre and post intervention, the assessment was made on Numerical Pain Rating Scale (NPRS, Functional Performance of Lower Extremity Scale (FPLES and by measured length at three reference positions. Independent T-test was used for statistical analysis. RESULTS: Both groups showed improvement in outcome in term of a decrease in pain score on NRPS, FPLES and measured reference lengths at all three positions (p-value 0.05 when results of pain score and measured reference length at three different positions were compared. However, on the FPLES, external rotator stretching technique was more effective than adductor stretching technique (p value < 0.05. CONCLUSION: The two studied sequence of piriformis stretching exercises have the same effect on outcomes in terms of clinically measured referenced length and decrease in pain score. Future studies will

  18. Process Parameter Identification in Thin Film Flows Driven by a Stretching Surface

    Directory of Open Access Journals (Sweden)

    Satyananda Panda

    2014-01-01

    Full Text Available The flow of a thin liquid film over a heated stretching surface is considered in this study. Due to a potential nonuniform temperature distribution on the stretching sheet, a temperature gradient occurs in the fluid which produces surface tension gradient at the free surface of the thin film. As a result, the free surface deforms and these deformations are advected by the flow in the stretching direction. This work focuses on the inverse problem of reconstructing the sheet temperature distribution and the sheet stretch rate from observed free surface variations. This work builds on the analysis of Santra and Dandapat (2009 who, based on the long-wave expansion of the Navier-Stokes equations, formulate a partial differential equation which describes the evolution of the thickness of a film over a nonisothermal stretched surface. In this work, we show that after algebraic manipulation of a discrete form of the governing equations, it is possible to reconstruct either the unknown temperature field on the sheet and hence the resulting heat transfer or the stretching rate of the underlying surface. We illustrate the proposed methodology and test its applicability on a range of test problems.

  19. Comparison electrical stimulation and passive stretching for blood glucose control type 2 diabetes mellitus patients

    Science.gov (United States)

    Arsianti, Rika Wahyuni; Parman, Dewy Haryanti; Lesmana, Hendy

    2018-04-01

    Physical exercise is one of the cornerstones for management and treatment type 2 diabetes mellitus. But not all people are able to perform physical exercise because of their physical limitation condition. The strategy for those people in this study is electrical stimulation and passive stretching. The aim of this study is to find out the effect of electrical stimulation and passive stretching to lowering blood glucose level. 20 subjects is divided into electrical stimulation and passive stretching group. The provision of electrical stimulation on lower extremities muscles for 30 minutes for electrical stimulation group (N=10). And other underwent passive stretching for 30 minutes (N=10). The result shows that blood glucose level is decrease from 192.9 ± 10.7087 mg/dL to 165.3 ± 10.527 mg/dL for electrical stimulation intervention group while for the passive stretching group the blood glucose decrease from 153 ± 12.468 mg/dL to 136.1 ± 12.346 mg/dL. Both electrical stimulation and passive stretching are effective to lowering blood glucose level and can be proposed for those people restricted to perform exercise.

  20. Mechanical stretch induces MMP-2 release and activation in lung endothelium: role of EMMPRIN.

    Science.gov (United States)

    Haseneen, Nadia A; Vaday, Gayle G; Zucker, Stanley; Foda, Hussein D

    2003-03-01

    High-volume mechanical ventilation leads to ventilator-induced lung injury. This type of lung injury is accompanied by an increased release and activation of matrix metalloproteinases (MMPs). To investigate the mechanism leading to the increased MMP release, we systematically studied the effect of mechanical stretch on human microvascular endothelial cells isolated from the lung. We exposed cells grown on collagen 1 BioFlex plates to sinusoidal cyclic stretch at 0.5 Hz using the Flexercell system with 17-18% elongation of cells. After 4 days of cell stretching, conditioned media and cell lysate were collected and analyzed by gelatin, casein, and reverse zymograms as well as Western blotting. RT-PCR of mRNA extracted from stretched cells was performed. Our results show that 1) cyclic stretch led to increased release and activation of MMP-2 and MMP-1; 2) the activation of MMP-2 was accompanied by an increase in membrane type-1 MMP (MT1-MMP) and inhibited by a hydroxamic acid-derived inhibitor of MMPs (Prinomastat, AG3340); and 3) the MMP-2 release and activation were preceded by an increase in production of extracellular MMP inducer (EMMPRIN). These results suggest that cyclic mechanical stretch leads to MMP-2 activation through an MT1-MMP mechanism. EMMPRIN may play an important role in the release and activation of MMPs during lung injury.

  1. CH Stretching Region: Computational Modeling of Vibrational Optical Activity

    Czech Academy of Sciences Publication Activity Database

    Hudecová, Jana; Profant, V.; Novotná, P.; Baumruk, V.; Urbanová, M.; Bouř, Petr

    2013-01-01

    Roč. 9, č. 7 (2013), s. 3096-3108 ISSN 1549-9618 R&D Projects: GA ČR GAP208/11/0105; GA MŠk(CZ) LH11033 Grant - others:AV ČR(CZ) M200550902 Institutional support: RVO:61388963 Keywords : density-functional theory * circular-dichroism spectra * N-methyl acetamide * alpha-pinene * Raman Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.310, year: 2013

  2. An energetic model for macromolecules unfolding in stretching experiments

    Science.gov (United States)

    De Tommasi, D.; Millardi, N.; Puglisi, G.; Saccomandi, G.

    2013-01-01

    We propose a simple approach, based on the minimization of the total (entropic plus unfolding) energy of a two-state system, to describe the unfolding of multi-domain macromolecules (proteins, silks, polysaccharides, nanopolymers). The model is fully analytical and enlightens the role of the different energetic components regulating the unfolding evolution. As an explicit example, we compare the analytical results with a titin atomic force microscopy stretch-induced unfolding experiment showing the ability of the model to quantitatively reproduce the experimental behaviour. In the thermodynamic limit, the sawtooth force–elongation unfolding curve degenerates to a constant force unfolding plateau. PMID:24047874

  3. Transparent conducting film: Effect of mechanical stretching to ...

    Indian Academy of Sciences (India)

    Administrator

    posite was fixed to a tabletop clamp and unidirectionally stretched after cutting the paper support at two opposite sides. To hold the film under the stretched condition, both edges of stretched CNT-mat/transparent-film composite was then adhered to a PMMA substrate by epoxy glue and both the sheet resistance and the ...

  4. Effects of dynamic stretches on Isokinetic hamstring and Quadriceps ...

    African Journals Online (AJOL)

    In conclusion, dynamic stretches have positive effects on muscle strength, H/Q ratios and ROM. Therefore, dynamic stretches may increase performance and reduce the risk of injury to athletes. Keywords: Quadriceps; Hamstrings; Muscles Isokinetic; Dynamic stretches. South African Journal for Research in Sport, Physical ...

  5. Stretched cell cycle model for proliferating lymphocytes

    Science.gov (United States)

    Dowling, Mark R.; Kan, Andrey; Heinzel, Susanne; Zhou, Jie H. S.; Marchingo, Julia M.; Wellard, Cameron J.; Markham, John F.; Hodgkin, Philip D.

    2014-01-01

    Stochastic variation in cell cycle time is a consistent feature of otherwise similar cells within a growing population. Classic studies concluded that the bulk of the variation occurs in the G1 phase, and many mathematical models assume a constant time for traversing the S/G2/M phases. By direct observation of transgenic fluorescent fusion proteins that report the onset of S phase, we establish that dividing B and T lymphocytes spend a near-fixed proportion of total division time in S/G2/M phases, and this proportion is correlated between sibling cells. This result is inconsistent with models that assume independent times for consecutive phases. Instead, we propose a stretching model for dividing lymphocytes where all parts of the cell cycle are proportional to total division time. Data fitting based on a stretched cell cycle model can significantly improve estimates of cell cycle parameters drawn from DNA labeling data used to monitor immune cell dynamics. PMID:24733943

  6. Stagnation-Point Flow and Heat Transfer over a Nonlinearly Stretching/Shrinking Sheet in a Micropolar Fluid

    Directory of Open Access Journals (Sweden)

    Khairy Zaimi

    2014-01-01

    Full Text Available This paper considers the problem of a steady two-dimensional stagnation-point flow and heat transfer of an incompressible micropolar fluid over a nonlinearly stretching/shrinking sheet. A similarity transformation is employed to convert the partial differential equations into nonlinear ordinary ones which are then solved numerically using a shooting method. Numerical results obtained are presented graphically, showing the effects of the micropolar or material parameter and the stretching/shrinking parameter on the flow field and heat transfer characteristics. The dual solutions are found to exist in a limited range of the stretching/shrinking parameter for the shrinking case, while unique solutions are possible for all positive values of the stretching/shrinking parameter (stretching case. It is also observed that the skin friction coefficient and the magnitude of the local Nusselt number increase as the material parameter increases.

  7. Comparison of the effects of hamstring stretching using proprioceptive neuromuscular facilitation with prior application of cryotherapy or ultrasound therapy

    Science.gov (United States)

    Magalhães, Francisco Elezier Xavier; Junior, Arlindo Rodrigues de Mesquita; Meneses, Harnold’s Tyson de Sousa; Moreira dos Santos, Rayele Pricila; Rodrigues, Ezaine Costa; Gouveia, Samara Sousa Vasconcelos; Gouveia, Guilherme Pertinni de Morais; Orsini, Marco; Bastos, Victor Hugo do Vale; Machado, Dionis de Castro Dutra

    2015-01-01

    [Purpose] Stretching using proprioceptive neuromuscular facilitation involve physiological reflex mechanisms through submaximal contraction of agonists which activate Golgi organ, promoting the relaxation reflex. The aim of this study was to evaluate the effects of proprioceptive neuromuscular facilitation alone and with prior application of cryotherapy and thermotherapy on hamstring stretching. [Subjects and Methods] The sample comprised of 32 young subjects with hamstring retraction of the right limb. The subjects were randomly allocated to four groups: the control, flexibility PNF, flexibility PNF associated with cryotherapy, flexibility PNF in association with ultrasound therapy. [Results] After 12 stretching sessions, experimental groups showed significant improvements compared to the control group. Moreover, we did not find any significant differences among the experimental groups indicating PNF stretching alone elicits similar results to PNF stretching with prior administration of cryotherapy or thermotherapy. [Conclusion] PNF without other therapy may be a more practical and less expensive choice for clinical care. PMID:26157261

  8. Comparison of the effects of hamstring stretching using proprioceptive neuromuscular facilitation with prior application of cryotherapy or ultrasound therapy.

    Science.gov (United States)

    Magalhães, Francisco Elezier Xavier; Junior, Arlindo Rodrigues de Mesquita; Meneses, Harnold's Tyson de Sousa; Moreira Dos Santos, Rayele Pricila; Rodrigues, Ezaine Costa; Gouveia, Samara Sousa Vasconcelos; Gouveia, Guilherme Pertinni de Morais; Orsini, Marco; Bastos, Victor Hugo do Vale; Machado, Dionis de Castro Dutra

    2015-05-01

    [Purpose] Stretching using proprioceptive neuromuscular facilitation involve physiological reflex mechanisms through submaximal contraction of agonists which activate Golgi organ, promoting the relaxation reflex. The aim of this study was to evaluate the effects of proprioceptive neuromuscular facilitation alone and with prior application of cryotherapy and thermotherapy on hamstring stretching. [Subjects and Methods] The sample comprised of 32 young subjects with hamstring retraction of the right limb. The subjects were randomly allocated to four groups: the control, flexibility PNF, flexibility PNF associated with cryotherapy, flexibility PNF in association with ultrasound therapy. [Results] After 12 stretching sessions, experimental groups showed significant improvements compared to the control group. Moreover, we did not find any significant differences among the experimental groups indicating PNF stretching alone elicits similar results to PNF stretching with prior administration of cryotherapy or thermotherapy. [Conclusion] PNF without other therapy may be a more practical and less expensive choice for clinical care.

  9. String Stretching, Frequency Modulation, and Banjo Clang

    OpenAIRE

    Politzer, David

    2014-01-01

    The banjo’s floating bridge, string break angle, and flexible drumhead all contribute to substantial audio range frequency modulation. From the world of electronic music synthesis, it is known that modulating higher frequency sounds with lower acoustic frequencies leads to metallic and bell-like tone. The mechanics of the banjo does just that quite naturally, modulating fundamentals and harmonics with the motion of the bridge. In technical terms, with a floating bridge, string stretching is f...

  10. The stretch zone of automotive steel sheets

    Indian Academy of Sciences (India)

    The stretch zone of automotive steel sheets. L' AMBRIŠKO1,∗ and L PEŠEK2. 1Institute of Structural Engineering, Faculty of Civil Engineering,. Technical University of Košice, Vysokoškolská 4, 042 00 Košice, Slovak Republic. 2Department of Materials Science, Faculty of Metallurgy,. Technical University of Košice, Letná 9, ...

  11. Acute effect of muscle stretching on the steadiness of sustained submaximal contractions of the plantar flexor muscles.

    Science.gov (United States)

    Kato, Emika; Vieillevoye, Stéphanie; Balestra, Costantino; Guissard, Nathalie; Duchateau, Jacques

    2011-02-01

    This paper examines the acute effect of a bout of static stretches on torque fluctuation during an isometric torque-matching task that required subjects to sustain isometric contractions as steady as possible with the plantar flexor muscles at four intensities (5, 10, 15, and 20% of maximum) for 20 s. The stretching bout comprised five 60-s passive stretches, separated by 10-s rest. During the torque-matching tasks and muscle stretching, the torque (active and passive) and surface electromyogram (EMG) of the medial gastrocnemius (MG), soleus (Sol), and tibialis anterior (TA) were continuously recorded. Concurrently, changes in muscle architecture (fascicle length and pennation angle) of the MG were monitored by ultrasonography. The results showed that during stretching, passive torque decreased and fascicle length increased gradually. Changes in these two parameters were significantly associated (r(2) = 0.46; P stretches induced greater torque fluctuation (P muscles with no change in coactivation. Furthermore, stretching maneuvers produced a greater decrease (∼15%; P stretches can decrease torque steadiness by increasing muscle compliance and EMG activity of muscles around the joint. The relative influence of such adaptations, however, may depend on the torque level during the torque-matching task.

  12. Spontaneous bending of pre-stretched bilayers.

    Science.gov (United States)

    DeSimone, Antonio

    2018-01-01

    We discuss spontaneously bent configurations of pre-stretched bilayer sheets that can be obtained by tuning the pre-stretches in the two layers. The two-dimensional nonlinear plate model we use for this purpose is an adaptation of the one recently obtained for thin sheets of nematic elastomers, by means of a rigorous dimensional reduction argument based on the theory of Gamma-convergence (Agostiniani and DeSimone in Meccanica. doi:10.1007/s11012-017-0630-4, 2017, Math Mech Solids. doi:10.1177/1081286517699991, arXiv:1509.07003, 2017). We argue that pre-stretched bilayer sheets provide us with an interesting model system to study shape programming and morphing of surfaces in other, more complex systems, where spontaneous deformations are induced by swelling due to the absorption of a liquid, phase transformations, thermal or electro-magnetic stimuli. These include bio-mimetic structures inspired by biological systems from both the plant and the animal kingdoms.

  13. Dynamics and structure of stretched flames

    Energy Technology Data Exchange (ETDEWEB)

    Law, C.K. [Princeton Univ., NJ (United States)

    1993-12-01

    This program aims to gain fundamental understanding on the structure, geometry, and dynamics of laminar premixed flames, and relate these understanding to the practical issues of flame extinction and stabilization. The underlying fundamental interest here is the recent recognition that the response of premixed flames can be profoundly affected by flame stretch, as manifested by flow nonuniformity, flame curvature, and flame/flow unsteadiness. As such, many of the existing understanding on the behavior of premixed flames need to be qualitatively revised. The research program consists of three major thrusts: (1) detailed experimental and computational mapping of the structure of aerodynamically-strained planar flames, with emphasis on the effects of heat loss, nonequidiffusion, and finite residence time on the flame thickness, extent of incomplete reaction, and the state of extinction. (2) Analytical study of the geometry and dynamics of stretch-affected wrinkled flame sheets in simple configurations, as exemplified by the Bunsen flame and the spatially-periodic flame, with emphasis on the effects of nonlinear stretch, the phenomena of flame cusping, smoothing, and tip opening, and their implications on the structure and burning rate of turbulent flames. (3) Stabilization and blowoff of two-dimensional inverted premixed and stabilization and determining the criteria governing flame blowoff. The research is synergistically conducted through the use of laser-based diagnostics, computational simulation of the flame structure with detailed chemistry and transport, and mathematical analysis of the flame dynamics.

  14. Stretch Moduli of Ribonucleotide Embedded Short DNAs

    Science.gov (United States)

    Chiu, Hsiang-Chih; Koh, Kyung Duk; Riedo, Elisa; Storici, Francesca

    2013-03-01

    Understanding the mechanical properties of DNA is essential to comprehending the dynamics of many cellular functions. DNA deformations are involved in many mechanisms when genetic information needs to be stored and used. In addition, recent studies have found that Ribonucleotides (rNMPs) are among the most common non-standard nucleotides present in DNA. The presences of rNMPs in DNA might cause mutation, fragility or genotoxicity of chromosome but how they influence the structure and mechanical properties of DNA remains unclear. By means of Atomic Force Microscopy (AFM) based single molecule spectroscopy, we measure the stretch moduli of double stranded DNAs (dsDNA) with 30 base pairs and 5 equally embedded rNMPs. The dsDNAs are anchored on gold substrate via thiol chemistry, while the AFM tip is used to pick up and stretch the dsDNA from its free end through biotin-streptavidin bonding. Our preliminary results indicate that the inclusion of rNMPs in dsDNA might significantly change its stretch modulus, which might be important in some biological processes.

  15. Elastography Study of Hamstring Behaviors during Passive Stretching

    Science.gov (United States)

    Le Sant, Guillaume; Ates, Filiz; Brasseur, Jean-Louis; Nordez, Antoine

    2015-01-01

    Introduction The mechanical properties of hamstring muscles are usually inferred from global passive torque/angle relationships, in combination with adjoining tissues crossing the joint investigated. Shear modulus measurement provides an estimate of changes in muscle-tendon stiffness and passive tension. This study aimed to assess the passive individual behavior of each hamstring muscle in different stretching positions using shear wave elastography. Methods/Results The muscle shear modulus of each hamstring muscle was measured during a standardized slow passive knee extension (PKE, 80% of maximal range of motion) on eighteen healthy male volunteers. Firstly, we assessed the reliability of the measurements. Results were good for semitendinosus (ST, CV: 8.9%-13.4%), semimembranosus (SM, CV: 10.3%-11.2%) and biceps femoris long-head (BF-lh, CV: 8.6%-13.3%), but not for biceps femoris short-head (BF-sh, CV: 20.3%-44.9%). Secondly, we investigated each reliable muscle in three stretch positions: 70°, 90° and 110° of hip flexion. The results showed different values of shear modulus for the same amount of perceived stretch, with the highest measurements in the high-flexed hip situation. Moreover, individual muscles displayed different values, with values increasing or BF-lh, SM and ST, respectively. The inter-subject variability was 35.3% for ST, 27.4% for SM and 30.2% for BF-lh. Conclusion This study showed that the hip needs to be high-flexed to efficiently tension the hamstrings, and reports a higher muscle-tendon stress tolerance at 110° of hip angle. In addition muscles have different passive behaviors, and future works will clarify if it can be linked with rate of injury. PMID:26418862

  16. Elastography Study of Hamstring Behaviors during Passive Stretching.

    Directory of Open Access Journals (Sweden)

    Guillaume Le Sant

    Full Text Available The mechanical properties of hamstring muscles are usually inferred from global passive torque/angle relationships, in combination with adjoining tissues crossing the joint investigated. Shear modulus measurement provides an estimate of changes in muscle-tendon stiffness and passive tension. This study aimed to assess the passive individual behavior of each hamstring muscle in different stretching positions using shear wave elastography.The muscle shear modulus of each hamstring muscle was measured during a standardized slow passive knee extension (PKE, 80% of maximal range of motion on eighteen healthy male volunteers. Firstly, we assessed the reliability of the measurements. Results were good for semitendinosus (ST, CV: 8.9%-13.4%, semimembranosus (SM, CV: 10.3%-11.2% and biceps femoris long-head (BF-lh, CV: 8.6%-13.3%, but not for biceps femoris short-head (BF-sh, CV: 20.3%-44.9%. Secondly, we investigated each reliable muscle in three stretch positions: 70°, 90° and 110° of hip flexion. The results showed different values of shear modulus for the same amount of perceived stretch, with the highest measurements in the high-flexed hip situation. Moreover, individual muscles displayed different values, with values increasing or BF-lh, SM and ST, respectively. The inter-subject variability was 35.3% for ST, 27.4% for SM and 30.2% for BF-lh.This study showed that the hip needs to be high-flexed to efficiently tension the hamstrings, and reports a higher muscle-tendon stress tolerance at 110° of hip angle. In addition muscles have different passive behaviors, and future works will clarify if it can be linked with rate of injury.

  17. Short Durations of Static Stretching when Combined with Dynamic Stretching do not Impair Repeated Sprints and Agility

    Science.gov (United States)

    Wong, Del P.; Chaouachi, Anis; Lau, Patrick W.C.; Behm, David G.

    2011-01-01

    This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performed (90 s total). Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. Key points The duration of combined static and dynamic stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit and reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). No significant differences in RSA and COD between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. The short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. PMID:24149890

  18. The effect of heat applied with stretch to increase range of motion: a systematic review.

    Science.gov (United States)

    Nakano, Jiro; Yamabayashi, Cristiane; Scott, Alex; Reid, W Darlene

    2012-08-01

    Application of heat to muscle is commonly advocated to enhance the efficacy of stretching. However, the effect of this combined therapy using different methods of heating, applied to different muscles, and after one or multiple treatments, is not known. To perform a systematic review to address the question: Does stretching augmented by heat application result in greater gains in range of motion (ROM) compared to stretch alone? The following databases were searched for original articles that evaluated our question: MEDLINE, EMBASE, CINAHL, the Cochrane Central Register of Controlled Trials, SPORTDiscus and PEDro databases. After title and abstract screening followed by full-text screening, the quality of included articles was assessed and their data was abstracted. Screening, data abstraction and quality assessment was performed and consensus was achieved by two reviewers. Range of motion (ROM) data were synthesized by meta-analyses for overall effect and subgroup analysis according to muscle group, method of heat application, single or multiple treatments, and reported tightness of muscle. Twelve studies were included and reported the effects of stretch with or without heat on ROM of 352 participants. Heat applications included ultrasound, shortwave diathermy and hot packs. Meta-analyses and subgroup analyses demonstrated greater increases in ROM after heat and stretch (H + S) than heat alone. Subgroup analysis of muscle groups and the method of heat application showed some trends, but no significant differences. Multiple treatments (more so than single treatments) showed consistent treatment effects of H + S versus stretch alone amongst subgroups. Muscles described as tight did not show a greater treatment effect in response to H + S compared to muscles not reported as tight. Heating provides an added benefit on stretch related gains of ROM in healthy people. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Activation of stretch-activated channels and maxi-K+ channels by membrane stress of human lamina cribrosa cells.

    LENUS (Irish Health Repository)

    Irnaten, Mustapha

    2009-01-01

    The lamina cribrosa (LC) region of the optic nerve head is considered the primary site of damage in glaucomatous optic neuropathy. Resident LC cells have a profibrotic potential when exposed to cyclical stretch. However, the mechanosensitive mechanisms of these cells remain unknown. Here the authors investigated the effects of membrane stretch on cell volume change and ion channel activity and examined the associated changes in intracellular calcium ([Ca(2+)](i)).

  20. The Relevance of Stretch Intensity and Position: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Nikos eApostolopoulos

    2015-08-01

    Full Text Available Stretching exercises to increase the range of motion (ROM of joints have been used by sports coaches and medical professionals for improving performance and rehabilitation. The ability of connective and muscular tissues to change their architecture in response to stretching is important for their proper function, repair and performance. Given the dearth of relevant data in the literature, this review examined two key elements of stretching: stretch intensity and stretch position; and their significance to ROM, delayed onset muscle soreness (DOMS, and inflammation in different populations. A search of three databases, Pub-Med, Google Scholar, and Cochrane Reviews, identified 152 articles, which were subsequently categorized into four groups; athletes (n = 24, clinical (n = 29, elderly (n = 12, and general population (n = 87. The use of different populations facilitated a wider examination of the stretching components and their effects. All 152 articles incorporated information regarding duration, frequency and stretch position, whereas only 79 referred to the intensity of stretching and 22 of these 79 studies were deemed high quality. It appears that the intensity of stretching is relatively under-researched, and the importance of body position and its influence on stretch intensity, is largely unknown. In conclusion, this review has highlighted areas for future research, including stretch intensity and position and their effect on musculo-tendinous tissue, in relation to the sensation of pain, delayed onset muscle soreness, inflammation, as well as muscle health and performance

  1. Hamstring Stiffness Returns More Rapidly After Static Stretching Than Range of Motion, Stretch Tolerance, and Isometric Peak Torque.

    Science.gov (United States)

    Hatano, Genki; Suzuki, Shigeyuki; Matsuo, Shingo; Kataura, Satoshi; Yokoi, Kazuaki; Fukaya, Taizan; Fujiwara, Mitsuhiro; Asai, Yuji; Iwata, Masahiro

    2017-12-18

    Hamstring injuries are common, and lack of hamstring flexibility may predispose to injury. Static stretching increases range of motion (ROM) but also results in reduced muscle strength after stretching. The effects of stretching on the hamstring muscles and the duration of these effects remain unclear. To determine the effects of static stretching on the hamstrings and the duration of these effects. Randomized crossover study. University laboratory. Twenty-four healthy volunteers. We measured the torque-angle relationship (ROM, passive torque (PT) at the onset of pain, and passive stiffness) and isometric muscle force using an isokinetic dynamometer. After a 60-minute rest, the ROM of the dynamometer was set at maximum tolerable intensity; this position was maintained for 300 seconds while static passive torque (SPT) was measured continuously. We remeasured the torque-angle relationship and isometric muscle force after rest periods of 10, 20, and 30 minutes. Change in SPT during stretching; changes in ROM, PT at the onset of pain, passive stiffness, and isometric muscle force before stretching compared with 10, 20, and 30 minutes after stretching. SPT decreased significantly during stretching. Passive stiffness decreased significantly 10 and 20 minutes after stretching, but there was no significant pre- vs. post-stretching difference after 30 minutes. PT at the onset of pain and ROM increased significantly after stretching at all rest intervals, while isometric muscle force decreased significantly after all rest intervals. The effect of static stretching on passive stiffness of the hamstrings was not maintained as long as the changes in ROM, stretch tolerance, and isometric muscle force. Therefore, frequent stretching is necessary to improve the viscoelasticity of the muscle-tendon unit. Muscle force was decreased for 30 minutes after stretching; this should be considered prior to activities requiring maximal muscle strength.

  2. Extension by faulting, stretching and magma intrusion in Ethiopia

    Science.gov (United States)

    Bastow, I. D.; Keir, D.

    2012-12-01

    The 2001-2004 Ethiopia Afar Geoscientific Lithospheric Experiment showed that high seismic wavespeed, dense, mafic crustal intrusions exist beneath many zones of Quaternary magmatism in the Main Ethiopian rift, and that crustal thinning is minimal. From these observations, a consensus quickly emerged that extension presently occurs not by ductile stretching and brittle faulting but by magma intrusion. Striking InSAR images and accompanying seismic data from the 2005 Afar diking episode provided further compelling evidence in support of the magma assisted rifting hypothesis. Patterns of mantle seismic anisotropy, constrained by a combination of body and surface-wave analysis showed that melt intrusion likely also plays an important role in accommodating extension at greater depths in the extending plate. Evidence from further north in Afar, however, where crustal thickness decreases abruptly into the Danakil Depression, is not so easily explained by the magma assisted rifting hypothesis. Subsidence of the newly forming margin towards and below sea level, and eruption of voluminous basalt flows, is likely the result of late-stage thinning of the heavily intruded, weakened plate just before the onset of seafloor spreading. Faulting, stretching and magma intrusion are thus each important, but at different times during breakup. Combining, not isolating, these mechanisms of strain in new rifting models and appreciating how plate strength varies during rifting is essential in developing a clearer understanding of the incomplete geological record that documents continental breakup over time.

  3. SHORT DURATIONS OF STATIC STRETCHING WHEN COMBINED WITH DYNAMIC STRETCHING DO NOT IMPAIR REPEATED SPRINTS AND AGILITY

    OpenAIRE

    Del P. Wong; Anis Chaouachi; Patrick W.C. Lau; David G. Behm

    2011-01-01

    This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performe...

  4. Efficacy of static stretching and proprioceptive neuromuscular facilitation stretch on hamstrings length after a single session.

    Science.gov (United States)

    O'Hora, John; Cartwright, Abigail; Wade, Clive D; Hough, Alan D; Shum, Gary L K

    2011-06-01

    A number of studies have investigated the efficacy of several repetitions of proprioceptive neuromuscular facilitation stretching (PNF) and static stretching (SS). However, there is limited research comparing the effects of a single bout of these stretching maneuvers. The aim of this study was to compare the effectiveness of a single bout of a therapist-applied 30-second SS vs. a single bout of therapist-applied 6-second hamstring (agonist) contract PNF. Forty-five healthy subjects between the ages of 21 and 35 were randomly allocated to 1 of the 2 stretching groups or a control group, in which no stretching was received. The flexibility of the hamstring was determined by a range of passive knee extension, measured using a universal goniometer, with the subject in the supine position and the hip at 90° flexion, before and after intervention. A significant increase in knee extension was found for both intervention groups after a single stretch (SS group = 7.53°, p < 0.01 and PNF group = 11.80°, p < 0.01). Both interventions resulted in a significantly greater increase in knee extension when compared to the control group (p < 0.01). The PNF group demonstrated significantly greater gains in knee extension compared to the SS group (mean difference 4.27°, p < 0.01). It can be concluded that a therapist applied SS or PNF results in a significant increase in hamstring flexibility. A hamstring (agonist) contract PNF is more effective than an SS in a single stretching session. These findings are important to physiotherapists or trainers working in clinical and sporting environments. Where in the past therapists may have spent time conducting multiple repetitions of a PNF and an SS, a single bout of either technique may be considered just as effective. A key component of the study methodology was the exclusion of a warm-up period before stretching. Therefore, the findings of efficacy of a single PNF are of particular relevance in sporting environments and busy clinical

  5. SHORT DURATIONS OF STATIC STRETCHING WHEN COMBINED WITH DYNAMIC STRETCHING DO NOT IMPAIR REPEATED SPRINTS AND AGILITY

    Directory of Open Access Journals (Sweden)

    Del P. Wong

    2011-06-01

    Full Text Available This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA and change of direction (COD. Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s. Three dynamic stretching exercises of 30 s duration were then performed (90 s total. Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p < 0.001. However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (< 90 s static stretching may not have provided sufficient stimulus to elicit performance impairments

  6. Correlation between acute and short-term changes in flexibility using two stretching techniques.

    Science.gov (United States)

    Beltrão, N B; Ritti-Dias, R M; Pitangui, A C R; De Araújo, R C

    2014-12-01

    This study aimed to determine whether increases in flexibility following a single session predict increases in flexibility after a short-term stretching training program involving static stretching (SS) or proprioceptive neuromuscular facilitation (PNF) techniques. 70 adults (aged 18-30 years) of both sexes were randomly assigned to 2 groups: PNF (2 series of contract-relax stretching) and SS (static stretching for 1 min). Both stretching protocols were performed for 7 consecutive days. Active knee extension was evaluated before and after the first session and one day after the end of the intervention. Two-way ANOVA showed significant flexibility gains for both groups and no difference between them. The changes in flexibility after the first intervention session were strongly correlated with the changes after the training program in both groups (PNF r=0.82, p=0.001; SS: r=0.82, p=0.001). Linear regression showed that the increases in flexibility predicted the gains after both training programs (PNF: r(2)=0.67, p=0.001; SS: r(2)=0.61, p=0.005). In conclusion, the acute changes in flexibility after a single session of PNF and SS predict the gains in flexibility after longer-term training -programs. © Georg Thieme Verlag KG Stuttgart · New York.

  7. Upper body force production after a low-volume static and dynamic stretching.

    Science.gov (United States)

    Leone, D C P G; Pezarat, P; Valamatos, M J; Fernandes, O; Freitas, S; Moraes, A C

    2014-01-01

    This study investigated the acute effect of a low-volume static and dynamic stretching on maximal isometric peak force (MIPF), time to maximal isometric force (TMIF), rate of force production (RFP) and average amplitude of the surface EMG (AvgEMG) of the main agonist muscles acting on the bench press maximum isometric force exercise. Thirty subjects were randomly divided into three groups: static stretch (SG: 22.8 ± 5.6 years, 176.6 ± 3.5 cm, 74.4 ± 5.9 kg), dynamic stretch (DG: 21.4 ± 3.9 years, 178.4 ± 7.2 cm, 71.7 ± 8.2 kg) and control group (CG: 20.4 ± 3.6 years, 179.8 ± 5.8 cm, 74.4 ± 9.8 kg). SG performed two 30-s repetitions and DG performed 10 repetitions of each of the two different exercises for the pectoralis major and triceps brachii. The MIPF, TMIF, RFP and AvgEMG of the pectoralis major (sternocostal part) and triceps brachii (long and lateral head) were measured before and immediately after the stretching protocols. A significant decrease in the MIPF from pre- to post-stretching was observed in both SG (p force parameters. No significant differences in the TMIF and RFP from pre- to post-stretching were found in the three groups. The SG showed a significant (p static and dynamic stretching adversely affects efforts of muscle maximal strength of the upper limb muscles studied, but it does not seem to affect TMIF or RFP.

  8. Viscous flows stretching and shrinking of surfaces

    CERN Document Server

    Mehmood, Ahmer

    2017-01-01

    This authored monograph provides a detailed discussion of the boundary layer flow due to a moving plate. The topical focus lies on the 2- and 3-dimensional case, considering axially symmetric and unsteady flows. The author derives a criterion for the self-similar and non-similar flow, and the turbulent flow due to a stretching or shrinking sheet is also discussed. The target audience primarily comprises research experts in the field of boundary layer flow, but the book will also be beneficial for graduate students.

  9. Stretched exponential dynamics of coupled logistic maps on a small-world network

    Science.gov (United States)

    Mahajan, Ashwini V.; Gade, Prashant M.

    2018-02-01

    We investigate the dynamic phase transition from partially or fully arrested state to spatiotemporal chaos in coupled logistic maps on a small-world network. Persistence of local variables in a coarse grained sense acts as an excellent order parameter to study this transition. We investigate the phase diagram by varying coupling strength and small-world rewiring probability p of nonlocal connections. The persistent region is a compact region bounded by two critical lines where band-merging crisis occurs. On one critical line, the persistent sites shows a nonexponential (stretched exponential) decay for all p while for another one, it shows crossover from nonexponential to exponential behavior as p → 1 . With an effectively antiferromagnetic coupling, coupling to two neighbors on either side leads to exchange frustration. Apart from exchange frustration, non-bipartite topology and nonlocal couplings in a small-world network could be a reason for anomalous relaxation. The distribution of trap times in asymptotic regime has a long tail as well. The dependence of temporal evolution of persistence on initial conditions is studied and a scaling form for persistence after waiting time is proposed. We present a simple possible model for this behavior.

  10. MHD biconvective flow of Powell Eyring nanofluid over stretched surface

    Science.gov (United States)

    Naseem, Faiza; Shafiq, Anum; Zhao, Lifeng; Naseem, Anum

    2017-06-01

    The present work is focused on behavioral characteristics of gyrotactic microorganisms to describe their role in heat and mass transfer in the presence of magnetohydrodynamic (MHD) forces in Powell-Eyring nanofluids. Implications concerning stretching sheet with respect to velocity, temperature, nanoparticle concentration and motile microorganism density were explored to highlight influential parameters. Aim of utilizing microorganisms was primarily to stabilize the nanoparticle suspension due to bioconvection generated by the combined effects of buoyancy forces and magnetic field. Influence of Newtonian heating was also analyzed by taking into account thermophoretic mechanism and Brownian motion effects to insinuate series solutions mediated by homotopy analysis method (HAM). Mathematical model captured the boundary layer regime that explicitly involved contemporary non linear partial differential equations converted into the ordinary differential equations. To depict nanofluid flow characteristics, pertinent parameters namely bioconvection Lewis number Lb, traditional Lewis number Le, bioconvection Péclet number Pe, buoyancy ratio parameter Nr, bioconvection Rayleigh number Rb, thermophoresis parameter Nt, Hartmann number M, Grashof number Gr, and Eckert number Ec were computed and analyzed. Results revealed evidence of hydromagnetic bioconvection for microorganism which was represented by graphs and tables. Our findings further show a significant effect of Newtonian heating over a stretching plate by examining the coefficient values of skin friction, local Nusselt number and the local density number. Comparison was made between Newtonian fluid and Powell-Eyring fluid on velocity field and temperature field. Results are compared of with contemporary studies and our findings are found in excellent agreement with these studies.

  11. The effect of two types of stretching on flexibility in selected joints in youth soccer players

    Directory of Open Access Journals (Sweden)

    Andrea Mahrová

    2014-03-01

    Full Text Available Background: The nature of soccer causes overloading of certain muscles and muscle groups that are most often involved in typical training activities of players. Often the absence of additional leisure-time activities typical for children and adolescents leads to an increased risk of muscle imbalance. Objective: We were interested in the occurrence of muscle imbalance, specifically an occurrence of muscle shortening and limited flexibility of the spine as well as decreased range of motion (ROM in selected joints among young soccer players. Methods: The players were randomly selected to take part in the study. Twelve young soccer players took part in the first group and thirteen in the second group (age 13 years, body weight 40.5 ± 3.9 vs. 41.5 ± 7.8 kg, height 150.0 ± 5.0 vs. 153.0 ± 9.8 cm. The first team performed only static stretching exercises at the end of the training session and the other team performed, except for static stretching, also dynamic stretching exercises always at the beginning of the training session. The effect of the stretching program on range of motion in chosen joints was assessed by 2 × 2 repeated-measures ANOVA (stretching methods × time. The statistical significance of a-level was set to .05 and partial ηp2. Results: Pre-test measurements revealed an occurrence of muscle shortening and limited ROM of the spine and selected joints mostly in the pelvis and lower limbs in all study participants. Comparison of ROM in selected joints between pre-test and post-test in program including both static and dynamic stretching showed significant increase of left hip during flexion (p = .03, ηp2 = .20. The program with only static stretching showed significant decrease the ROM of ankle plantar flexion (p = .04, ηp2 = .18. We did not find any significant difference between stretching programs on ROM. As for muscle shortening, both side improvements (higher number of subjects with no

  12. Twist-stretch profiles of DNA chains

    Science.gov (United States)

    Zoli, Marco

    2017-06-01

    Helical molecules change their twist number under the effect of a mechanical load. We study the twist-stretch relation for a set of short DNA molecules modeled by a mesoscopic Hamiltonian. Finite temperature path integral techniques are applied to generate a large ensemble of possible configurations for the base pairs of the sequence. The model also accounts for the bending and twisting fluctuations between adjacent base pairs along the molecules stack. Simulating a broad range of twisting conformation, we compute the helix structural parameters by averaging over the ensemble of base pairs configurations. The method selects, for any applied force, the average twist angle which minimizes the molecule’s free energy. It is found that the chains generally over-twist under an applied stretching and the over-twisting is physically associated to the contraction of the average helix diameter, i.e. to the damping of the base pair fluctuations. Instead, assuming that the maximum amplitude of the bending fluctuations may decrease against the external load, the DNA molecule first over-twists for weak applied forces and then untwists above a characteristic force value. Our results are discussed in relation to available experimental information albeit for kilo-base long molecules.

  13. High-throughput time-stretch imaging flow cytometry for multi-class classification of phytoplankton.

    Science.gov (United States)

    Lai, Queenie T K; Lee, Kelvin C M; Tang, Anson H L; Wong, Kenneth K Y; So, Hayden K H; Tsia, Kevin K

    2016-12-12

    Time-stretch imaging has been regarded as an attractive technique for high-throughput imaging flow cytometry primarily owing to its real-time, continuous ultrafast operation. Nevertheless, two key challenges remain: (1) sufficiently high time-stretch image resolution and contrast is needed for visualizing sub-cellular complexity of single cells, and (2) the ability to unravel the heterogeneity and complexity of the highly diverse population of cells - a central problem of single-cell analysis in life sciences - is required. We here demonstrate an optofluidic time-stretch imaging flow cytometer that enables these two features, in the context of high-throughput multi-class (up to 14 classes) phytoplantkton screening and classification. Based on the comprehensive feature extraction and selection procedures, we show that the intracellular texture/morphology, which is revealed by high-resolution time-stretch imaging, plays a critical role of improving the accuracy of phytoplankton classification, as high as 94.7%, based on multi-class support vector machine (SVM). We also demonstrate that high-resolution time-stretch images, which allows exploitation of various feature domains, e.g. Fourier space, enables further sub-population identification - paving the way toward deeper learning and classification based on large-scale single-cell images. Not only applicable to biomedical diagnostic, this work is anticipated to find immediate applications in marine and biofuel research.

  14. The realignment of carbon nanotubes in polymer/CNT composites by mechanical stretching method

    Science.gov (United States)

    Dai, Jianfeng; Wang, Qing; Li, Weixue; Wei, Zhiqiang; Jiang, Jinlong

    2007-07-01

    A new convenient and simple technique for the realignment of carbon nanotubes in single walled carbon nanotubes (SWNTs) reinforced polymer composites by stretching the semidried matrices in the same direction repeatedly is presented in this paper. Every SWNT in the matrices having an angular displacement tend to align in the stretching direction due to a torque exerting on it. Only when SWNT aligned along the stretching direction, the torque equal zero. CNT/polymer composites SWNT/epoxy resin and SWNT/PMMA were prepared by solution casting and in situ polymerization respectively. SEM demonstrates that SWNTs are well dispersed in the composite matrix and aligning in the stretching direction. The electrical and mechanical tests indicate that the composites prepared by this method present highly anisotropic properties. The mechanical properties of composites rise with the increase of SWNT concentration, composites showed higher mechanical properties such as the Young's modulus, tensile strength and elongation along the stretched direction than perpendicular to it. A sharp increase of the conductivity value was observed for both SWNT/epoxy and SWNT/PMMA composites just with low SWNT weight fractions. With respect to pure PMMA, the electrical conductivity of 3 wt. % aligned SWNT nanocomposite increased by 9 orders of magnitude, up to 10 -3 S/cm.

  15. Two stretching treatments for the hamstrings: proprioceptive neuromuscular facilitation versus kinesio taping.

    Science.gov (United States)

    Chen, Che-Hsiu; Huang, Tsun-Shun; Chai, Huei-Ming; Jan, Mei-Hwa; Lin, Jiu-Jenq

    2013-02-01

    Recent studies have shown that the static stretch (SS) may adversely affect leg-muscle performance. The authors examined the short-term effects of 2 stretching exercises on hamstrings muscle before and after exercise. Crossover. Laboratory. 9 healthy, physically active men. There were 3 protocols in a randomized order with a 7-d interval: nonstretching (CON protocol), hamstrings static stretching (SS) with proprioceptive neuromuscular facilitation (PNF), and SS with kinesio-taping application on the hamstrings. Outcome measures included first-felt and maximum tolerant-felt range of motion (FROM and TROM), maximal knee-flexion peak torque (PT) at 180°/s, and hamstrings muscle stiffness. Groups were not different at prestretching in terms of hamstrings flexibility, PT, and muscle stiffness. At poststretching, both stretching protocols showed significant increases in FROM and TROM (P .05). The stretching protocols improve hamstrings flexibility immediately, but after exercise hamstrings peak torque is diminished in the SS+PNF but not in the SS+Taping group. This means that SS+Taping can prevent negative results from exercise, which may prevent muscle injury.

  16. Clinical massage and modified Proprioceptive Neuromuscular Facilitation stretching in males with latent myofascial trigger points.

    Science.gov (United States)

    Trampas, Athanasios; Kitsios, Athanasios; Sykaras, Evagelos; Symeonidis, Stamatios; Lazarou, Lazaros

    2010-08-01

    To determine the immediate effects of modified Proprioceptive Neuromuscular Facilitation (PNF) stretching (group I) versus Myofascial Trigger Point (MTrP) therapy plus modified PNF stretching (group II) in comparison to a control group receiving no treatment. Randomized, assessor-blind, (3 x 4) mixed-model repeated measures. University laboratory. Thirty physically active males with tight hamstrings and at least one latent MTrP on muscles innervated by the lumbosacral, sciatic, tibial and common peroneal nerves. Knee range of motion (ROM), stretch perception, pressure pain threshold (PPT) and subjective pain intensity. Outcomes were evaluated at baseline, immediately after treatment, at 10 and 30 min. Significant changes over time occurred for group II in all outcomes (p < or = 0.001). Group II also showed lower pain intensity scores than group I immediately post-treatment (p = 0.045) and a strong clinical effect over group I in ROM at all follow-ups (effect sizes = 0.9-1.0, p < or = 0.05). Other differences were found between both stretching groups as compared to the control group (p < or = 0.05). The results indicate immediate pre- to post-treatment benefits from MTrP therapy combined with modified PNF stretching in young and physically active males with latent MTrPs. 2010 Elsevier Ltd. All rights reserved.

  17. Influence of Stretching-Segment Storage Length on Urban Traffic Flow in Signalized Intersection

    Directory of Open Access Journals (Sweden)

    Weiwei Guo

    2011-12-01

    Full Text Available Intelligent traffic control is influenced by Stretching-segment design, parameters optimization of traffic control have to consider saturation flow rate in approach. Many intersections with different stretching-segment design forms are selected to study on saturation flow rate at peak rush hour and ordinary time hour, the characteristic of saturation flow rate in green time is analyzed. Based on the real traffic situation, the influence of the length of stretching-segment storage to straight-cross flow rate was explored in this study. The data showed that the duration and stability of saturation flow rate were highly influenced by the length of stretching-segment storage. A probabilistic computing model was proposed, which analyzed the effect of the length of stretching-segment to the flow rate and described the impact of vehicles in the upstream. Finally, the attenuate regulation of the straight-cross flow rate in green phase is developed by the analysis of vehicle's blocking.

  18. EFFECTIVENESS OF ECCENTRIC TRAINING, DYNAMIC RANGE OF MOTION EXERCISES AND STATIC STRETCHING ON FLEXIBILITY OF HAMSTRING MUSCLE AMONG FOOTBALL PLAYERS.

    Directory of Open Access Journals (Sweden)

    Askar P.V

    2015-12-01

    Full Text Available Background: Hamstring stretch is an important part of treatment programs aimed at decreasing the likelihood of hamstring injury. Few studies have examine the effect of eccentric training, static stretching and dynamic range of motion(DROM exercise in improving hamstring flexibility this study compares the effect of eccentric training and static stretching in improving hamstring flexibility. The purpose of this study was to determine the effects of Eccentric training, Static stretching and Dynamic range of motion (DROM exercise in improving hamstring flexibility and the second objective is find which technique is more effective in improving hamstring flexibility when compared with a control group. Study design is Experimental pre-test post-test design. Methods: 88 male subjects with limited hamstring flexibility were recruited for this study were assigned to four group. Group1 received eccentric training, group2 received dynamic range of motion exercise, group3 received static stretching and group4 was served as control group. Hamstring length was measured pre intervention and post intervention using a self-monitored active knee extension test. Results: Eccentric training, static stretching and dynamic range of motion exercise showed a significant increase in hamstring length between pre and post intervention. Following a between group analysis done by independent t test revealed a significant difference between group1 group2 and group3 Conclusion: It is concluded that eccentric training, dynamic range of motion (DROM exercise and static stretching groups improved hamstring flexibility.

  19. Effects of stretching the scalene muscles on slow vital capacity.

    Science.gov (United States)

    Lee, Juncheol; Hwang, Sehee; Han, Seungim; Han, Dongwook

    2016-06-01

    [Purpose] The purpose of this study was to examine whether stretching of the scalene muscles would improve slow vital capacity (SVC). [Subjects and Methods] The subjects of this study were 20 healthy female students to whom the study's methods and purpose were explained and their agreement for participation was obtained. The SVC was measured using spirometry (Pony FX, COSMED Inc., Italy). The intervention used was stretching of the scalene muscles. Stretching was carried out for 15 min, 10 times at per each portion of scalene muscles: the anterior, middle, and posterior parts. [Results] Expiratory vital capacity (EVC) and tidal volume (Vt) noticeably increased after stretching. However, there were no changes in any of the SVC items in the control group. [Conclusion] This study demonstrated that stretching of the scalene muscles can effectively improve SVC. In particular, we confirmed that stretching of the scalene muscles was effective in increasing EVC and Vt, which are items of SVC.

  20. Mechanical stretch influence on lifetime of dielectric elastomer films

    Science.gov (United States)

    Iannarelli, A.; Niasar, M. Ghaffarian

    2017-04-01

    Film pre-stretching is a widely adopted solution to improve dielectric strength of the DEA systems. However, to date, long term reliability of this solution has not been investigated. In this work it is explored how the dielectric elastomer lifetime is affected by film pre-stretching. The dielectric loss of soft polydimethylsiloxane (PDMS) films is studied for different stretch ratios by measuring tanδ. Additionally, time-to-breakdown was measured at DC electric stress for different stretch ratios. For this purpose, accelerated life test (ALT) were performed. The results obtained are compared with non-pre-stretched samples. This study suggests that no additional dielectric losses are caused by film stretching up to 80% of original dimensions.

  1. Calcineurin /NFAT activation-dependence of leptin synthesis and vascular growth in response to mechanical stretch

    Directory of Open Access Journals (Sweden)

    Nadia Soudani

    2016-09-01

    Full Text Available Background and Aims- Hypertension and obesity are important risk factors of cardiovascular disease. They are both associated with high leptin levels and have been shown to promote vascular hypertrophy, through the RhoA/ROCK and ERK1/2 phosphorylation. Calcineurin/NFAT activation also induces vascular hypertrophy by upregulating various genes. This study aimed to decipher whether a crosstalk exists between the RhoA/ROCK pathway, Ca+2/calcineurin/NFAT pathway, and ERK1/2 phosphorylation in the process of mechanical stretch-induced vascular smooth muscle cell (VSMC hypertrophy and leptin synthesis. Methods and Results- Rat portal vein (RPV organ culture was used to investigate the effect of mechanical stretch and exogenous leptin (3.1 nM on VSMC hypertrophy and leptin synthesis. Results showed that stretching the RPV significantly upregulated leptin secretion, mRNA and protein expression, which were inhibited by the calcium channel blocker nifedipine (10 μM, the selective calcineurin inhibitor FK506 (1 nM and the ERK1/2 inhibitor PD98059 (1 μM. The transcription inhibitor actinomycin D (0.1M and the translation inhibitor cycloheximide (1 mM significantly decreased stretch-induced leptin protein expression. Mechanical stretch or leptin caused an increase in wet weight changes and protein synthesis, considered as hypertrophic markers, while they were inhibited by FK506 (0.1 nM; 1 nM. In addition, stretch or exogenous leptin significantly increased calcineurin activity and MCIP1 expression whereas leptin induced NFAT nuclear translocation in VSMCs. Moreover, in response to stretch or exogenous leptin, the Rho inhibitor C3 exoenzyme (30 ng/mL, the ROCK inhibitor Y-27632 (10 μM, and the actin depolymerization agents Latrunculin B (50 nM and cytochalasin D (1 μM reduced calcineurin activation and NFAT nuclear translocation. ERK1/2 phosphorylation was inhibited by FK506 and C3. Conclusions- Mechanical stretch-induced VSMC hypertrophy and leptin

  2. Proprioceptive neuromuscular facilitation stretching : mechanisms and clinical implications.

    Science.gov (United States)

    Sharman, Melanie J; Cresswell, Andrew G; Riek, Stephan

    2006-01-01

    Proprioceptive neuromuscular facilitation (PNF) stretching techniques are commonly used in the athletic and clinical environments to enhance both active and passive range of motion (ROM) with a view to optimising motor performance and rehabilitation. PNF stretching is positioned in the literature as the most effective stretching technique when the aim is to increase ROM, particularly in respect to short-term changes in ROM. With due consideration of the heterogeneity across the applied PNF stretching research, a summary of the findings suggests that an 'active' PNF stretching technique achieves the greatest gains in ROM, e.g. utilising a shortening contraction of the opposing muscle to place the target muscle on stretch, followed by a static contraction of the target muscle. The inclusion of a shortening contraction of the opposing muscle appears to have the greatest impact on enhancing ROM. When including a static contraction of the target muscle, this needs to be held for approximately 3 seconds at no more than 20% of a maximum voluntary contraction. The greatest changes in ROM generally occur after the first repetition and in order to achieve more lasting changes in ROM, PNF stretching needs to be performed once or twice per week. The superior changes in ROM that PNF stretching often produces compared with other stretching techniques has traditionally been attributed to autogenic and/or reciprocal inhibition, although the literature does not support this hypothesis. Instead, and in the absence of a biomechanical explanation, the contemporary view proposes that PNF stretching influences the point at which stretch is perceived or tolerated. The mechanism(s) underpinning the change in stretch perception or tolerance are not known, although pain modulation has been suggested.

  3. Randomized Trial of Modified Stretching Exercise Program for Menstrual Low Back Pain.

    Science.gov (United States)

    Chen, Huei-Mein; Hu, Hsou-Mei

    2018-03-01

    This study aimed to examine the effectiveness of a modified stretching exercise program on young women with menstrual low back pain. Overall, 127 young women were randomly assigned to the experimental ( n = 63) and control ( n = 64) groups. The experimental group followed the modified stretching exercise program, whereas the control group performed their usual activities. At 1, 4, 8, and 12 months, the experimental group had significantly lower scores on the visual analog scale for pain (95% confidence interval [CI] = [0.73, 1.96]; p < .05) and the Oswestry Low Back Pain Disability Questionnaire than the control group (95% CI = [0.68, 2.03]; p < .001). At 12 months, the experimental group showed significantly higher exercise self-efficacy than the control group (95% CI = [-6.87, 0.62]; p = .003). These findings can be used to enhance self-care capabilities by using the modified stretching exercise program for young women with menstrual low back pain.

  4. Computing the Stretch Factor of Paths, Trees, and Cycles in Weighted Fixed Orientation Metrics

    DEFF Research Database (Denmark)

    Wulff-Nilsen, Christian

    2008-01-01

    Let G be a graph embedded in the L_1-plane. The stretch factor of G is the maximum over all pairs of distinct vertices p and q of G of the ratio L_1^G(p,q)/L_1(p,q), where L_1^G(p,q) is the L_1-distance in G between p and q. We show how to compute the stretch factor of an n-vertex path in O(n*(lo......(n*(log n)^2) worst-case time and O(n) space and we mention generalizations to trees and cycles, to general weighted fixed orientation metrics, and to higher dimensions....

  5. Dispersion Relation of an OH-Stretching Vibration from Inelastic X-Ray Scattering

    Science.gov (United States)

    Winkler, Björn; Friedrich, Alexandra; Wilson, Dan J.; Haussühl, Eiken; Krisch, Michael; Bosak, Alexei; Refson, Keith; Milman, Victor

    2008-08-01

    We show that recent advances now allow us to measure the wave vector dependence of OH-stretching frequencies at energies around 400 meV by inelastic x-ray scattering using ID28@ESRF. We found a large, unexpected dispersion when we measured the dispersion relations of the hydrogen stretching frequencies of diaspore, α-AlOOH, where the hydrogen atoms participate in a hydrogen bond of intermediate strength. We can account for this behavior with density functional perturbation theory calculations and a simple model based on H-H interactions.

  6. Effects of contract-relax vs static stretching on stretch-induced strength loss and length-tension relationship

    DEFF Research Database (Denmark)

    Balle, S S; Magnusson, S P; McHugh, M P

    2015-01-01

    The purpose of this study was to determine the acute effects of contract-relax stretching (CRS) vs static stretching (SS) on strength loss and the length-tension relationship. We hypothesized that there would be a greater muscle length-specific effect of CRS vs SS. Isometric hamstring strength...... loss compared with SS. These results support the use of SS for stretching the hamstrings....

  7. The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects

    OpenAIRE

    O'Sullivan, Kieran; Murray, Elaine; Sainsbury, David

    2009-01-01

    Abstract Background Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. Methods A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM). 18 previously injured indi...

  8. LABOR GYMNASTICS: STRETCHING EXERCISE X FLEXIONAMENT

    Directory of Open Access Journals (Sweden)

    Jacqueline Amorin Anchieta Borges da Silva, Isabel Cristina Taranto e Fernanda Piasecki

    2006-12-01

    Full Text Available Nowadays, there are many opportunities for the society to live a healthful and long life. At the same time, never people was so sedentary and without harmony. Without a healthy body and with “an occupied mind” the human loses exactly what more it needs: the disposal to produce, to coexist and to live a good life. In this context, the present research aimed to revise some terms related to labor gymnastics, which is focused in the prevention of risks related to hours of working and in the reduction of muscular tension levels that may be originated during a day of work. Thus, the present study will make a differentiation between the use of stretching and flexionament during labor gymnastic sessions.

  9. Stretched Lens Array Photovoltaic Concentrator Technology Developed

    Science.gov (United States)

    Piszczor, Michael F., Jr.; O'Neill, Mark J.

    2004-01-01

    Solar arrays have been and continue to be the mainstay in providing power to nearly all commercial and government spacecraft. Light from the Sun is directly converted into electrical energy using solar cells. One way to reduce the cost of future space power systems is by minimizing the size and number of expensive solar cells by focusing the sunlight onto smaller cells using concentrator optics. The stretched lens array (SLA) is a unique concept that uses arched Fresnel lens concentrators to focus sunlight onto a line of high-efficiency solar cells located directly beneath. The SLA concept is based on the Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) design that was used on NASA's New Millennium Deep Space 1 mission. The highly successful asteroid/comet rendezvous mission (1998 to 2001) demonstrated the performance and long-term durability of the SCARLET/SLA solar array design and set the foundation for further improvements to optimize its performance.

  10. Aerothermodynamic properties of stretched flames in enclosures

    Science.gov (United States)

    Rotman, D. A.; Oppenheim, A. K.

    Flames are stretched by being pulled along their frontal surface by the flow field in which they reside. Their trajectories tend to approach particle paths, acquiring eventually the role of contact boundaries, -interfaces between the burnt and unburnt medium that may broaden solely as a consequence of diffusion. Fundamental properties of flow fields governing such flames are determined here on the basis of the zero Mach number model, providng a rational method of approach to the computational analysis of combustion fields in enclosures where, besides the aerodynamic properties flow, the thermodynamic process of compression must be taken into account. To illustrate its application, the method is used to reveal the mechanism of formation of a tulip-shape flame in a rectangular enclosure under nonturbulent flow conditions.

  11. The Preliminary Stretching Effect on Mechanical Properties of Natural and Synthetic Polyamide fibres and Conformational Transitions

    Science.gov (United States)

    Aksakal, Baki; Phoshkina, Svetlana P.; Darvish, Diana M.; Tsobkallo, Ekaterina S.; Alekberov, Vilayet

    2007-04-01

    The preliminary stretching effect on mechanical properties of natural (wool, hair, and silk) and synthetic polyamide fibres (nylon, capron) and conformational transitions are investigated by using a tensile tester. It is shown that α-keratin fibres (wool and hair) show silk-like properties and properties of synthetic polyamide fibres for preliminary extension of 18-24% and 34-38%, respectively.

  12. Immediate Effects of Proprioceptive Neuromuscular Facilitation Stretching Programs Compared With Passive Stretching Programs for Hamstring Flexibility: A Critically Appraised Topic.

    Science.gov (United States)

    Hill, Kristian J; Robinson, Kendall P; Cuchna, Jennifer W; Hoch, Matthew C

    2017-11-01

    Clinical Scenario: Increasing hamstring flexibility through clinical stretching interventions may be an effective means to prevent hamstring injuries. However the most effective method to increase hamstring flexibility has yet to be determined. For a healthy individual, are proprioceptive neuromuscular facilitation (PNF) stretching programs more effective in immediately improving hamstring flexibility when compared with static stretching programs? Summary of Key Findings: A thorough literature search returned 195 possible studies; 5 studies met the inclusion criteria and were included. Current evidence supports the use of PNF stretching or static stretching programs for increasing hamstring flexibility. However, neither program demonstrated superior effectiveness when examining immediate increases in hamstring flexibility. Clinical Bottom Line: There were consistent findings from multiple low-quality studies that indicate there is no difference in the immediate improvements in hamstring flexibility when comparing PNF stretching programs to static stretching programs in physically active adults. Strength of Recommendation: Grade B evidence exists that PNF and static stretching programs equally increase hamstring flexibility immediately following the stretching program.

  13. Mixed quantum/classical approach to OH-stretch inelastic incoherent neutron scattering spectroscopy for ambient and supercooled liquid water and ice Ih

    International Nuclear Information System (INIS)

    Shi, L.; Skinner, J. L.

    2015-01-01

    OH-stretch inelastic incoherent neutron scattering (IINS) has been measured to determine the vibrational density of states (VDOS) in the OH-stretch region for liquid water, supercooled water, and ice Ih, providing complementary information to IR and Raman spectroscopies about hydrogen bonding in these phases. In this work, we extend the combined electronic-structure/molecular-dynamics (ES/MD) method, originally developed by Skinner and co-workers to simulate OH-stretch IR and Raman spectra, to the calculation of IINS spectra with small k values. The agreement between theory and experiment in the limit k → 0 is reasonable, further validating the reliability of the ES/MD method in simulating OH-stretch spectroscopy in condensed phases. The connections and differences between IINS and IR spectra are analyzed to illustrate the advantages of IINS over IR in estimating the OH-stretch VDOS

  14. A Stream Function Theory Based Calculation of Wave Kinematics for Very Steep Waves Using a Novel Non-linear Stretching Technique

    DEFF Research Database (Denmark)

    Stroescu, Ionut Emanuel; Sørensen, Lasse; Frigaard, Peter Bak

    2016-01-01

    A non-linear stretching method was implemented for stream function theory to solve wave kinematics for physical conditions close to breaking waves in shallow waters, with wave heights limited by the water depth. The non-linear stretching method proves itself robust, efficient and fast, showing good...

  15. Machine-Stitched E-textile Stretch Sensors

    Directory of Open Access Journals (Sweden)

    Guido Gioberto

    2016-07-01

    Full Text Available Truly wearable sensing poses challenges in many areas. To be successful, wearable sensors must preserve wearer comfort while providing accurate sensor data. Further, for widespread commercial production they must also be compatible with soft goods manufacturing. Here, we present a method of fabricating stretch sensors using common apparel sewing machinery. The response of sensors made using industrial coverstitch (two varieties and overlock machines are compared, and the sensor response of a bottom-thread coverstitch is characterized in depth. Three conductive thread structures are compared in the bottom-thread coverstitch sensor. Results show a consistent and repeatable response for 4- and 5-ply threads, while 2-ply thread displayed more noise and less repeatability. Finally, this sensor is applied in a spinal goniometry application in three garment structures, and sensor performance is compared to motion capture data. The fabrication approach is promising for wearable sensing applications due to its manufacturability and comfort.

  16. The effect of a four-week proprioceptive neuromuscular facilitation stretching program on isokinetic torque production.

    Science.gov (United States)

    Higgs, Fiona; Winter, Samantha L

    2009-08-01

    Flexibility is widely accepted as an important component of fitness, yet flexibility training can be detrimental to muscle performance particularly where a high number of stretch cycles are performed. The purpose of this study was to investigate whether chronic proprioceptive neuromuscular facilitation (PNF) stretch training could successfully improve the knee flexion range of motion without having a detrimental effect on the peak isokinetic torque of the quadriceps. The minimum knee angle in flexion and the peak isokinetic quadriceps torque were measured at 120 and 270 degrees xs. Subjects then participated in a 4-week quadriceps flexibility training program consisting of 3 cycles of PNF stretching performed 3 times a week. The range of motion was recorded before and after the first stretching session of each week. At the end of the 4-week period, the peak isokinetic quadriceps torque and flexibility were again measured. The mean (SE) improvement in the knee flexion range of motion over the whole program was 9.2 degrees (1.45 degrees ), and typical gains after a single stretching session were around 3 degrees . Post hoc analysis showed that the pretraining session range of motion was significantly improved in week 4 compared with the pretraining session range of motion in weeks 1 and 2 (p < 0.05). There was no change (p = 0.9635) in the peak isokinetic torque produced at 120 degrees xs (week 1: 121.9 (4.6) N x m; week 2: 121.9 (5.2) N x m) or at 270 degrees xs (week 1: 88.1 (3.4) N x m; week 2: 88.6 (4.9) N x m). These findings suggest that it is possible to improve flexibility using 3 PNF stretch cycles performed 3 times a week without altering muscle isokinetic strength characteristics.

  17. Force produced after stretch in sarcomeres and half-sarcomeres isolated from skeletal muscles

    Science.gov (United States)

    Minozzo, Fábio C.; Baroni, Bruno M.; Correa, José A.; Vaz, Marco A.; Rassier, Dilson E.

    2013-07-01

    The goal of this study was to evaluate if isolated sarcomeres and half-sarcomeres produce a long-lasting increase in force after a stretch is imposed during activation. Single and half-sarcomeres were isolated from myofibrils using micro-needles, which were also used for force measurements. After full force development, both preparations were stretched by different magnitudes. The sarcomere length (SL) or half-sarcomere length variations (HSL) were extracted by measuring the initial and final distances from the Z-line to the adjacent Z-line or to a region externally adjacent to the M-line of the sarcomere, respectively. Half-sarcomeres generated approximately the same amount of isometric force (29.0 +/- SD 15.5 nN.μm-2) as single sarcomeres (32.1 +/- SD 15.3 nN.μm-2) when activated. In both cases, the steady-state forces after stretch were higher than the forces during isometric contractions at similar conditions. The results suggest that stretch-induced force enhancement is partly caused by proteins within the half-sarcomere.

  18. In vitro assessment of ultraviolet protection of coloured cotton knitted fabrics with different structures under stretched and wet conditions.

    Science.gov (United States)

    Wong, W Y; Lam, J K C; Kan, C W; Postle, R

    2015-04-01

    Clothing provides intrinsic ultraviolet (UV) protection that can be improved by colouration. However, the daily wearing condition can undermine the UV protection of coloured clothing wherein garments are stretched by body movement and/or wetted by perspiration of wearers. Knitwear is an indispensable clothing in summer, but its UV protection against wearing conditions lacks extensive study especially in a fabric structural approach. This article aimed at narrowing the research gap by focusing on the UV protection against stretch and wetness provided by various knitted fabric constructions incorporating the knit, tuck and miss stitches. The results show that the black knitted fabrics exhibit a significant reduction in the UV protection factor by 53% on average at a 10% stretch level. Knitted fabrics with miss stitches retained good UV protection even when the fabrics were stretched by 20% of its original dimensions. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. Effects of acute stretching on the maximal expression of strength ...

    African Journals Online (AJOL)

    This study compared the effects of four treatments (n = 12 each) [10 minutes of quiet sitting, without stretching (NS); two minutes warm up on an arm ergometer at 25 watts resistance (WU); 10 second-hold static stretching (each) of the shoulder, chest and arm muscle groups (ST10); and two sets of 20 second-hold static ...

  20. The stretch reflex and the contributions of C David Marsden.

    Science.gov (United States)

    Bhattacharyya, Kalyan B

    2017-01-01

    The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching by increasing its contractility as long as the stretch is within physiological limits. For ages, it was thought that the stretch reflex was of short latency and it was synonymous with the tendon reflex, subserving the same spinal reflex arc. However, disparities in the status of the two reflexes in certain clinical situations led Marsden and his collaborators to carry out a series of experiments that helped to establish that the two reflexes had different pathways. That the two reflexes are dissociated has been proved by the fact that the stretch reflex and the tendon reflex, elicited by stimulation of the same muscle, have different latencies, that of the stretch reflex being considerably longer. They hypothesized that the stretch reflex had a transcortical course before it reached the spinal motor neurons for final firing. Additionally, the phenomenon of stimulus-sensitive cortical myoclonus lent further evidence to the presence of the transcortical loop where the EEG correlate preceded the EMG discharge. This concept has been worked out by later neurologists in great detail, and the general consensus is that indeed, the stretch reflex is endowed with a conspicuous transcortical component.

  1. Chaperones in Polyglutamine Aggregation : Beyond the Q-Stretch

    NARCIS (Netherlands)

    Kuiper, E. F. E.; de Mattos, Eduardo P.; Jardim, Laura B.; Kampinga, Harm H.; Bergink, Steven

    2017-01-01

    Expanded polyglutamine (polyQ) stretches in at least nine unrelated proteins lead to inherited neuronal dysfunction and degeneration. The expansion size in all diseases correlates with age at onset (AO) of disease and with polyQ protein aggregation, indicating that the expanded polyQ stretch is the

  2. Stretched exponential relaxation and ac universality in disordered dielectrics

    DEFF Research Database (Denmark)

    Milovanov, Alexander V.; Rypdal, Kristoffer; Juul Rasmussen, Jens

    2007-01-01

    are stretched exponential character of dielectric relaxation, power-law power spectral density, and anomalous dependence of ac conduction coefficient on frequency. We propose a self-consistent model of dielectric relaxation in which the relaxations are described by a stretched exponential decay function...

  3. Time and direction preparation of the long latency stretch reflex.

    Science.gov (United States)

    Nikaido, Yasutaka; Hatanaka, Ryota; Jono, Yasutomo; Nomura, Yoshifumi; Tani, Keisuke; Chujo, Yuta; Hiraoka, Koichi

    2016-06-01

    This study investigated time and direction preparation of motor response to force load while intending to maintain the finger at the initial neutral position. Force load extending or flexing the index finger was given while healthy humans intended to maintain the index finger at the initial neutral position. Electromyographic activity was recorded from the first dorsal interosseous muscle. A precue with or without advanced information regarding the direction of the forthcoming force load was given 1000ms before force load. Trials without the precue were inserted between the precued trials. A long latency stretch reflex was elicited by force load regardless of its direction, indicating that the long latency stretch reflex is elicited not only by muscle stretch afferents, but also by direction-insensitive sensations. Time preparation of motor response to either direction of force load enhanced the long latency stretch reflex, indicating that time preparation is not mediated by afferent discharge of muscle stretch. Direction preparation enhanced the long latency stretch reflex and increased corticospinal excitability 0-20ms after force load when force load was given in the direction stretching the muscle. These enhancements must be induced by preset of the afferent pathway mediating segmental stretch reflex. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. The stretch reflex and the contributions of C David Marsden

    Directory of Open Access Journals (Sweden)

    Kalyan B Bhattacharyya

    2017-01-01

    Full Text Available The stretch reflex or myotatic reflex refers to the contraction of a muscle in response to its passive stretching by increasing its contractility as long as the stretch is within physiological limits. For ages, it was thought that the stretch reflex was of short latency and it was synonymous with the tendon reflex, subserving the same spinal reflex arc. However, disparities in the status of the two reflexes in certain clinical situations led Marsden and his collaborators to carry out a series of experiments that helped to establish that the two reflexes had different pathways. That the two reflexes are dissociated has been proved by the fact that the stretch reflex and the tendon reflex, elicited by stimulation of the same muscle, have different latencies, that of the stretch reflex being considerably longer. They hypothesized that the stretch reflex had a transcortical course before it reached the spinal motor neurons for final firing. Additionally, the phenomenon of stimulus-sensitive cortical myoclonus lent further evidence to the presence of the transcortical loop where the EEG correlate preceded the EMG discharge. This concept has been worked out by later neurologists in great detail , and the general consensus is that indeed, the stretch reflex is endowed with a conspicuous transcortical component.

  5. Transparent conducting film: Effect of mechanical stretching to ...

    Indian Academy of Sciences (India)

    We describe in this paper a transparent conducting film (TCF). It is a fibrous layer of multiwalled carbon nanotubes (MWNTs), labeled a dilute CNT mat, that was prepared and unidirectionally stretched to improve both the optical and electrical properties. After stretching by 80% strain, transmittance at 550 nm wavelength ...

  6. The effects of acute self myofascial release (MFR) and stretching ...

    African Journals Online (AJOL)

    Baseline measurements were taken initially and then participants were randomly divided into four groups (control [n=10, static stretching [n=10], dynamic stretching [n=10] and self MFR [n=10]). Each group performed a 60-minute intervention. During the intervention programme the various groups took part in prescribed ...

  7. Transparent conducting film: Effect of mechanical stretching to ...

    Indian Academy of Sciences (India)

    Administrator

    The number of pixels inside a rectangle counted on the Adobe Photoshop. Figure 6. Sheet resistance and transmittance at 550 nm wave- length of a dilute CNT mat before and after stretch. Five sam- ples were stretched by 40 and 110% strain respectively and average data is shown in each case. A polyurethane elastomer.

  8. Does Postexercise Static Stretching Alleviate Delayed Muscle Soreness?

    Science.gov (United States)

    Buroker, Katherine C.; Schwane, James A.

    1989-01-01

    Because many experts recommend stretching after exercise to relieve muscle soreness, 23 subjects performed a 30-minute step test to induce delayed muscle soreness. There was neither temporary relief of pain immediately after stretching nor a reduction in pain during the 3-day postexercise period. (Author/SM)

  9. Mechanical stretch influence on lifetime of dielectric elastomer films

    NARCIS (Netherlands)

    Iannarelli, A.; Ghaffarian Niasar, M.; Bar-Cohen, Yoseph

    2017-01-01

    Film pre-stretching is a widely adopted solution to improve dielectric strength of the DEA systems. However, to date, long term reliability of this solution has not been investigated. In this work it is explored how the dielectric elastomer lifetime is affected by film pre-stretching. The dielectric

  10. The effect of calf stretching box on stretching calf muscle compliance: a prospective, randomized single-blinded controlled trial.

    Science.gov (United States)

    Chadchavalpanichaya, Navaporn; Srisawasdi, Gulapar; Suwannakin, Atchara

    2010-12-01

    To study the effect of calf stretching box usage in increasing the compliance of performing calf stretching exercise as compared to the conventional exercise method. To study the effect of calf stretching box usage in decreasing the calf muscle tightness and complications as compared to the conventional exercise method. Eighty patients older than 45 years old with calf muscles tightness were enrolled in a prospective, randomized single-blinded controlled trial at the out-patient Rehabilitation medicine clinic, Siriraj Hospital, Bangkok Thailand between April and August 2009. Patients were randomized into two groups, the study group (stretching by using calf stretching box) and the control group (stretching by the conventional exercise method). Patients in both groups were asked to hold the stretch for at least 1 minute and to perform the stretching program at least two times per day, every day for two weeks. Furthermore, they were asked to record the real frequency and duration of their exercise and complications in a logbook every day. Thirty-eight patients in each group completed the study. The baseline characteristics of the patients in both groups were similar. The study group had higher frequency and longer duration of performing calf stretching exercise than the control group. They also reported more decrease of calf muscle tightness with less pain complication (shoulder pain, knee pain, low back pain, and calf muscle pain) than the control group (p calf muscle and degree of ankle range of motion between the two groups. Stretching calf muscle with calf stretching box can increase compliance, decrease calf muscle tightness and decrease complications when compared with the conventional exercise method.

  11. The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects.

    Science.gov (United States)

    O'Sullivan, Kieran; Murray, Elaine; Sainsbury, David

    2009-04-16

    Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM). 18 previously injured individuals and 18 uninjured controls participated. On both days, four measurements of PKE ROM were recorded: (1) at baseline; (2) after warm-up; (3) after stretch (static or dynamic) and (4) after a 15-minute rest. Participants carried out both static and dynamic stretches, but on different days. Data were analysed using Anova. Across both groups, there was a significant main effect for time (p static stretching (p = 0.04) but significantly decreased after dynamic stretching (p = 0.013). The increased flexibility after warm-up and static stretching reduced significantly (p 0.05). Using ANCOVA to adjust for the non-significant (p = 0.141) baseline difference between groups, the previously injured group demonstrated a greater response to warm-up and static stretching, however this was not statistically significant (p = 0.05). Warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not, in agreement with previous findings on uninjured controls. The effect of warm-up and static stretching on flexibility was greater in those with reduced flexibility post-injury, but this did not reach statistical significance. Further prospective research is required to validate the hypothesis that increased flexibility improves outcomes. ACTRN12608000638336.

  12. The effects of stretching and stabilization exercise on the improvement of spastic shoulder function in hemiplegic patients.

    Science.gov (United States)

    You, Young Youl; Her, Jin Gang; Woo, Ji-Hea; Ko, Taesung; Chung, Sin Ho

    2014-04-01

    [Purpose] This study investigated the effects of stretching and joint stabilization exercises applied to spastic shoulder joints on improving shoulder dysfunction in hemiplegic patients. [Subjects and Methods] Hemiplegic patients were classified into three groups: one group received 30 min of traditional exercise therapy for the spastic shoulder joint; one group received 30 min stretching; and one group received 15 min of stretching and 15 min of joint stabilization exercises. The exercises were performed once a day, five times per week for eight weeks. Changes in the pathologic thickness of tendons and recovery of shoulder function were compared among the three groups. Differences among the three groups before the experiment, at four weeks, and at eight weeks were analyzed using repeated measures ANOVA. [Results] The stretching and joint stabilization exercise therapy group showed greater improvement in shoulder function than the traditional exercise therapy group and the stretching only group. This group also showed greater decreases in the pathologic thickness of tendons, than the other groups. [Conclusion] This study demonstrated that an exercise therapy program that combined stretching and joint stabilization exercise was more effective than other exercises for improvement of spastic shoulder joint dysfunction in hemiplegic patients.

  13. Bruxism: Is There an Indication for Muscle-Stretching Exercises?

    Science.gov (United States)

    Gouw, Simone; de Wijer, Anton; Creugers, Nico Hj; Kalaykova, Stanimira I

    Bruxism is a common phenomenon involving repetitive activation of the masticatory muscles. Muscle-stretching exercises are a recommended part of several international guidelines for musculoskeletal disorders and may be effective in management of the jaw muscle activity that gives rise to bruxism. However, most studies of muscle-stretching exercises have mainly focused on their influence on performance (eg, range of motion, coordination, and muscle strength) of the limb or trunk muscles of healthy individuals or individuals with sports-related injuries. Very few have investigated stretching of the human masticatory muscles and none muscle-stretching exercises in the management of (sleep) bruxism. This article reviews the literature on muscle-stretching exercises and their potential role in the management of sleep bruxism or its consequences in the musculoskeletal system.

  14. Acute effect of different stretching methods on isometric muscle strength

    Directory of Open Access Journals (Sweden)

    Gabriel Vasconcellos de Lima Costa e Silva

    2014-03-01

    This study investigated the acute effect of static stretching methods (SS and proprioceptive neuromuscular facilitation (PNF on the static muscle strength (SMS. Eleven young male subjects with strength training experience, performed 3 tests with a 48h interval between them, randomly selected, where each one subject carried out all procedures: a hand grip without stretching; b hand grip preceded by static stretching of wrist flexors muscles; c hand grip preceded by PNF stretching of wrist flexors muscles. The Shapiro-Wilk test verified the normality of data, and a one-way ANOVA with repeated measures, followed by Tukey’s post hoc test, evaluated the differences between the groups. The significance was set at p 0.05. In conclusion, both stretching methods had caused negative effects on isometric strength, reducing its levels.

  15. Influence of passive stretching on inhibition of disuse atrophy and hemodynamics of rat soleus muscle

    OpenAIRE

    Kimura, Shigefumi; Inaoka, Pleiades Tiharu; Yamazaki, Toshiaki

    2012-01-01

    The purpose of this study was to determine the infl uence of passive stretching on inhibition of disuse atrophy and hemodynamics among longitudinal regions of the rat soleus muscle. Disuse muscle atrophy was induced by hindlimb suspension for two weeks. Muscle blood flow was evaluated using thallium-201 (201Tl) which is a radiotracer that has been reported to be useful to assess blood perfusion in skeletal muscle. Thirty-nine male Wistar rats were divided randomly into 5 groups: control (C: n...

  16. New Insights into Lamellar Structure Development and SAXS/WAXD Sequence Appearance During Uniaxial Stretching of Amorphous Poly(ethylene terephthalate) Above Glass Transition Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami,D.; Burger, C.; Ran, S.; Avila-Orta, C.; Sics, I.; Chu, B.; Chiao, S.; Hsiao, B.; Kikutani, T.

    2008-01-01

    An in situ study of structure formation in amorphous poly(ethylene terephthalate) (PET) during uniaxial stretching at a temperature 30 C above glass transition temperature was carried out using synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) techniques. Three major deformation-induced structure transitions were confirmed. (1) At small strains, the applied load increased initially but leveled off afterward. Sporadic isotropic crystallization without preferred orientation was observed by WAXD, where no hierarchical structure was seen by SAXS. (2) At intermediate strains, strain hardening took place. Although WAXD showed persistent progression of isotropic crystallization, SAXS indicated formation of a layered structure as well as a fibrillar domain in large scale. This behavior is not consistent with the mechanisms for shish-kebab or spinodal-assisted structure formation. Instead, it can be explained by flow-induced demixing of crystal and amorphous phases through layerlike flocking motion perpendicular to the stretching direction. (3) At high strains, the ratio between the applied load and strain was about constant. In this stage, crystal reorientation and lateral crystal growth took place. The corresponding structure changes could be categorized into three subregions. In the first region, the (010) crystalline plane began to orient. In the second region, the (100) crystalline plane began to orient. In the last region, the structure change became stable and the sample eventually broke apart.

  17. Acute effects of different stretching durations on passive torque, mobility, and isometric muscle force.

    Science.gov (United States)

    Matsuo, Shingo; Suzuki, Shigeyuki; Iwata, Masahiro; Banno, Yasuhiro; Asai, Yuji; Tsuchida, Wakako; Inoue, Takayuki

    2013-12-01

    Static stretching is widely applied in various disciplines. However, the acute effects of different durations of stretching are unclear. Therefore, this study was designed to investigate the acute effects of different stretching durations on muscle function and flexibility, and provide an insight into the optimal duration of static stretching. This randomized crossover trial included 24 healthy students (17 men and 7 women) who stretched their right hamstrings for durations of 20, 60, 180, and 300 seconds in a random order. The following outcomes were assessed using an isokinetic dynamometer as markers of lower-limb function and flexibility: static passive torque (SPT), dynamic passive torque (DPT), stiffness, straight leg raise (SLR), and isometric muscle force. Static passive torque was significantly decreased after all stretching durations (p stretching compared with that after 20-second stretching, and stiffness decreased significantly after 180- and 300-second stretching (p stretching (p stretching durations (p stretching than after 20-second stretching and higher after 300-second stretching than after 60-second stretching (p muscle force significantly decreased after all stretching durations (p stretching is associated with a decrease in SPT but an increase in SLR. Over 180 seconds of stretching was required to decrease DPT and stiffness, but isometric muscle force decreased regardless of the stretching duration. In conclusion, these results indicate that longer durations of stretching are needed to provide better flexibility.

  18. Pre-exercise stretching does not impact upon running economy.

    Science.gov (United States)

    Hayes, Philip R; Walker, Adrian

    2007-11-01

    Pre-exercise stretching has been widely reported to reduce performance in tasks requiring maximal or near-maximal force or torque. The purpose of this study was to compare the effects of 3 different pre-exercise stretching routines on running economy. Seven competitive male middle and long-distance runners (mean +/- SD) age: 32.5 +/- 7.7 years; height: 175.0 +/- 8.8 cm; mass: 67.8 +/- 8.6 kg; V(.-)O2max: 66.8 +/- 7.0 ml x kg(-1) x min(-1)) volunteered to participate in this study. Each participant completed 4 different pre-exercise conditions: (a) a control condition, (b) static stretching, (c) progressive static stretching, and (d) dynamic stretching. Each stretching routine consisted of 2 x 30-second stretches for each of 5 exercises. Dependent variables measured were sit and reach test before and after each pre-exercise routine, running economy (ml x kg(-1) x km(-1)), and steady-state oxygen uptake (ml x kg(-1) x min(-1)), which were measured during the final 3 minutes of a 10-minute run below lactate threshold. All 3 stretching routines resulted in an increase in the range of movement (p = 0.008). There was no change in either running economy (p = 0.915) or steady-state V(.-)O2 (p = 0.943). The lack of change in running economy was most likely because it was assessed after a period of submaximal running, which may have masked any effects from the stretching protocols. Previously reported reductions in performance have been attributed to reduced motor unit activation, presumably IIX. In this study, these motor units were likely not to have been recruited; this may explain the unimpaired performance. This study suggests that pre-exercise stretching has no impact upon running economy or submaximal exercise oxygen cost.

  19. STUDY TO COMPARE THE EFFECTIVENESS OF STATIC STRETCH AND HOLD RELAX TECHNIQUE OVER HAMSTRING FLEXIBILITY

    Directory of Open Access Journals (Sweden)

    Shanthi C

    2014-10-01

    Full Text Available Background: Numerous studies have documented on flexibility of muscles. Flexibility is defined as the ability of the muscles to lengthen allowing one joint or more than one joint in a series to move through a range of motion .Flexibility allows tissue to accommodate more easily to stress thus minimizing or preventing muscle injury. But this study sought to identify the study to compare the effectiveness of Static stretch and Hold relax technique over the hamstring flexibility. Methods: 30 healthy male adults with Hamstring tightness aged 21 to 35 years selected from general population through simple randomized technique. Samples are divided into two groups, static stretch Group-I(no.15 and Group-II Hold relax (no.=15.The outcome was measured with help of sit & reach test to see the Hamstring flexibility. Results: Comparison of the post test values of the group I and group II shows a significant difference between the outcomes of two groups with a “t” calculated value of 0.738 (unpaired “t” test. Conclusion: Both static stretch and hold relax Technique can cause very highly significant result in Hamstring Flexibility, further comparison shows very high significant difference between two groups and concludes that hold relax is better than static stretch in Hamstring Flexibility.

  20. Reflectors Made from Membranes Stretched Between Beams

    Science.gov (United States)

    Dooley, Jennifer; Dragovan, Mark; Tolomeo, Jason

    2009-01-01

    Lightweight cylindrical reflectors of a proposed type would be made from reflective membranes stretched between pairs of identically curved and identically oriented end rails. In each such reflector, the curvature of the two beams would define the reflector shape required for the intended application. For example, the beams could be curved to define a reflector of parabolic cross section, so that light incident along the axis of symmetry perpendicular to the cylindrical axis would be focused to a line. In addition, by applying suitable forces to the ends of the beams, one could bend the beams to adjust the reflector surface figure to within a precision of the order of the wavelength of the radiation to be reflected. The figure depicts an example of beams shaped so that in the absence of applied forces, each would be flat on one side and would have a radius of curvature R on the opposite side. Alternatively, the curvature of the reflector-membrane side could be other than circular. In general, the initial curvature would be chosen to optimize the final reflector shape. Then by applying forces F between the beam ends in the positions and orientations shown in the figure, one could bend beams to adjust their shape to a closer approximation of the desired precise circular or noncircular curvature.

  1. COMPARISON OF EFFECTS OF ABDOMINAL STRETCHING EXERCISE AND COLD COMPRESS THERAPY ON MENSTRUAL PAIN INTENSITY IN TEENAGE GIRLS

    Directory of Open Access Journals (Sweden)

    Desta Ayu Cahya Rosyida

    2017-07-01

    Full Text Available Background: Pain during menstruation is not uncommon, especially in young women, which has an impact on their life activities. Objective: To examine the effect of abdominal stretching exercise and cold compress therapy on decreasing intensity of menstrual pain in teenage girls at SMK Bakti Indonesia Medika. Design: A Quasy Experimental Study with two group comparison pretest-postest design. There were 46 respondents selected in this study by consecutive sampling that consisted of 23 samples in the abdominal stretching exercise group and 23 samples in the cold compress group. The menstrual pain was measured using VAS (visual analog scale. Data were analyzed using Mann-Whitney, Chi-Square, and Wilcoxon test. Results: Findings showed that the mean of menstrual pain before intervention in the abdominal stretching exercise was 7.04 and in the cold compress therapy was 6.74 with p-value 0.211 (<0.05, which indicated that there was no mean difference of pain between both groups. However, after intervention, the menstrual pain was reduced from 7.04 to 1.91 (5.09 difference in the abdominal stretching exercise group; and from 6.74 to 5.52 (1.22 difference in the cold compress group with p-value 0.000 (<0.05, which indicated that there was statistically significant difference of menstrual pain before and after intervention, both abdominal stretching exercise and cold compress therapy. Conclusion: There were statistically significant effects of abdominal stretching exercise and cold compress therapy on menstrual pain in teenage girls. The abdominal stretching exercise is more effective than cold compress therapy in reducing menstrual pain intensity. Thus, it is suggested that abdominal stretching exercise can be an alternative choice of management of dysmenorrhea in teenage girls, and can be a part of subject in the education as non-pharmacological medicine.

  2. Effect of hip and knee position on tensor fasciae latae elongation during stretching: An ultrasonic shear wave elastography study.

    Science.gov (United States)

    Umehara, Jun; Ikezoe, Tome; Nishishita, Satoru; Nakamura, Masatoshi; Umegaki, Hiroki; Kobayashi, Takuya; Fujita, Kosuke; Ichihashi, Noriaki

    2015-12-01

    Decreased flexibility of the tensor fasciae latae is one factor that causes iliotibial band syndrome. Stretching has been used to improve flexibility or tightness of the muscle. However, no studies have investigated the effective stretching position for the tensor fasciae latae using an index to quantify muscle elongation in vivo. The aim of this study was to investigate the effects of hip rotation and knee angle on tensor fasciae latae elongation during stretching in vivo using ultrasonic shear wave elastography. Twenty healthy men participated in this study. The shear elastic modulus of the tensor fasciae latae was calculated using ultrasonic shear wave elastography. Stretching was performed at maximal hip adduction and maximal hip extension in 12 different positions with three hip rotation conditions (neutral, internal, and external rotations) and four knee angles (0°, 45°, 90°, and 135°). Two-way analysis of variance showed a significant main effect for knee angle, but not for hip rotation. The post-hoc test for knee angle indicated that the shear elastic modulus at 90° and 135° were significantly greater than those at 0° and 45°. Our results suggest that adding hip rotation to the stretching position with hip adduction and extension may have less effect on tensor fasciae latae elongation, and that stretching at >90° of knee flexion may effectively elongate the tensor fasciae latae. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Applying proprioceptive neuromuscular facilitation stretching: optimal contraction intensity to attain the maximum increase in range of motion in young males.

    Science.gov (United States)

    Kwak, Dong Ho; Ryu, Young Uk

    2015-07-01

    [Purpose] Proprioceptive neuromuscular facilitation (PNF) stretching is known to be effective in increasing joint ROM. The PNF stretching technique first induces an isometric contraction in the muscles to be stretched, but no agreement concerning the optimal contraction intensity has yet been reached. The purpose of the present study was to examine the effect of contraction intensity on ROM while applying PNF stretching. [Subjects and Methods] Sixty male subjects were randomly assigned to one of four groups (three experimental groups and one control group). Each experimental group applied one of three contraction intensities (100%, 60%, and 20%) defined by the MVIC ratio, and the control group did not receive any intervention during the experiment. PNF stretching was applied to left knee extensors to compare changes in the knee joint flexion angle. [Results] The results showed that the changes in ROM were larger for the 60% and 100% groups compared with the 20% group. The changes in ROM were lowest in the control group. [Conclusion] The present results indicate that while applying the PNF stretching, it is not necessary to apply the maximum intensity of muscle contraction. Moderate isometric contraction intensities may be optimal for healthy young males, while a sufficient effect can be obtained even with a low contraction intensity.

  4. Acute Effects of Different Methods of Stretching and Specific Warm-ups on Muscle Architecture and Strength Performance.

    Science.gov (United States)

    Sá, Marcos A; Matta, Thiago T; Carneiro, Simone P; Araujo, Carolina O; Novaes, Jefferson S; Oliveira, Liliam F

    2016-08-01

    Sá, MA, Matta, TT, Carneiro, SP, Araujo, CO, Novaes, JS, and Oliveira, LF. Acute effects of different methods of stretching and specific warm-ups on muscle architecture and strength performance. J Strength Cond Res 30(8): 2324-2329, 2016-The purpose of the study was to investigate the acute effects of 2 stretching interventions, proprioceptive neuromuscular facilitation (PNF) and passive static stretching (PSS), and a specific warm-up (SW) on the strength and architecture of the vastus laterallis and biceps femoris muscles in a subsequent performance on a strength training session (STS). Musculoskeletal ultrasound images were acquired from 9 men before and immediately after stretchings or a SW, and 10 minutes after a STS. The STS consisted of the following exercises: leg extension, leg curl, leg press, and hack machine squat. The PNF resulted in lower performance for all situations. The PSS and SW improved performance for the leg press compared with the PNF and controls (CSs). For the hack machine squat, SWs resulted in higher performance than stretching conditions. The vastus lateralis muscle fascicle length (FL) increases after a STS for PNF. The biceps femoris muscle showed a higher pennation angle 10 minutes after the STS for PSS; the FL increases immediately after PSS and then decreases 10 minutes after the STS for PSS. As per our results, the SWs should be performed before STSs, whereas PNF stretching should not be prescribed because this condition impairs subsequent performance. These results may assist health professionals in prescribing resistance training.

  5. Regional assignment of seven loci to 12p 13. 2-pter by PCR analysis of somatic cell hybrids containing the der(12) or the der(X) chromosome from a mesothelioma showing t(X; 12)(q22; p13)

    Energy Technology Data Exchange (ETDEWEB)

    Aerssens, J.; Chaffanet, M.; Baens, M.; Matthijs, G.; Van Den Berche, H.; Cassiman, J.J.; Marynen, P. (Arthritis and Metabolic Bone Disease Research Unit, Leuven (Belgium))

    1994-03-01

    Two somatic cell hybrids containing the der(12) or the der(X) from a mesothelioma with a translocation t(X;12) (q22;p13) as the only chromosomal change were generated to characterize the region of 12p12 containing the translocation breakpoint. Fluorescence in situ hybridization analysis showed the breakpoint on chromosome 12 to occur between VWF and D12S158. On the linkage map developed by J. Weissenbach et al., the breakpoints were located between DXS1106 and DCS1001 on chromosome X. PCR analysis based on genomic sequences, with DNA from both somatic cell hybrids, enabled mapping of CACNL1A1, FGF6, D12S370, D12S38OE, D12S381E, and D12S382E distally to the 12p13 breakpoint and to VWF. 11 refs., 2 figs., 1 tab.

  6. Magnitude and duration of stretch modulate fibroblast remodeling.

    Science.gov (United States)

    Balestrini, Jenna L; Billiar, Kristen L

    2009-05-01

    Mechanical cues modulate fibroblast tractional forces and remodeling of extracellular matrix in healthy tissue, healing wounds, and engineered matrices. The goal of the present study is to establish dose-response relationships between stretch parameters (magnitude and duration per day) and matrix remodeling metrics (compaction, strength, extensibility, collagen content, contraction, and cellularity). Cyclic equibiaxial stretch of 2-16% was applied to fibroblast-populated fibrin gels for either 6 h or 24 h/day for 8 days. Trends in matrix remodeling metrics as a function of stretch magnitude and duration were analyzed using regression analysis. The compaction and ultimate tensile strength of the tissues increased in a dose-dependent manner with increasing stretch magnitude, yet remained unaffected by the duration in which they were cycled (6 h/day versus 24 h/day). Collagen density increased exponentially as a function of both the magnitude and duration of stretch, with samples stretched for the reduced duration per day having the highest levels of collagen accumulation. Cell number and failure tension were also dependent on both the magnitude and duration of stretch, although stretch-induced increases in these metrics were only present in the samples loaded for 6 h/day. Our results indicate that both the magnitude and the duration per day of stretch are critical parameters in modulating fibroblast remodeling of the extracellular matrix, and that these two factors regulate different aspects of this remodeling. These findings move us one step closer to fully characterizing culture conditions for tissue equivalents, developing improved wound healing treatments and understanding tissue responses to changes in mechanical environments during growth, repair, and disease states.

  7. The effect of stretch-and-flow voice therapy on measures of vocal function and handicap.

    Science.gov (United States)

    Watts, Christopher R; Diviney, Shelby S; Hamilton, Amy; Toles, Laura; Childs, Lesley; Mau, Ted

    2015-03-01

    To investigate the efficacy of stretch-and-flow voice therapy as a primary physiological treatment for patients with hyperfunctional voice disorders. Prospective case series. Participants with a diagnosis of primary muscle tension dysphonia or phonotraumatic lesions due to hyperfunctional vocal behaviors were included. Participants received stretch-and-flow voice therapy structured once weekly for 6 weeks. Outcome variables consisted of two physiologic measures (s/z ratio and maximum phonation time), an acoustic measure (cepstral peak prominence [CPP]), and a measure of vocal handicap (voice handicap index [VHI]). All measures were obtained at baseline before treatment and within 2 weeks posttreatment. The s/z ratio, maximum phonation time, sentence CPP, and VHI showed statistically significant (P < 0.05) improvement through therapy. Effect sizes reflecting the magnitude of change were large for s/z ratio and VHI (d = 1.25 and 1.96 respectively), and moderate for maximum phonation time and sentence CPP (d = 0.79 and 0.74, respectively). This study provides supporting evidence for preliminary efficacy of stretch-and-flow voice therapy in a small sample of patients. The treatment effect was large or moderate for multiple outcome measures. The data provide justification for larger, controlled clinical trials on the application of stretch-and-flow voice therapy in the treatment of hyperfunctional voice disorders. Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  8. Kink and kink-like waves in pre-stretched Mooney-Rivlin viscoelastic rods

    Directory of Open Access Journals (Sweden)

    Y. Z. Wang

    2015-08-01

    Full Text Available The present paper theoretically investigates kink and kink-like waves propagating in pre-stretched Mooney-Rivlin viscoelastic rods. In the constitutive modeling, the Cauchy stress tensor is assumed to consist of an elastic part and a dissipative part. The asymptotic method is adopted to simplify the nonlinear dynamic equations in the limit of finite-small amplitude and long wavelength. Using the reductive perturbation method, we further derive the well-known far-field equation (i.e. the KdV-Burgers equation, to which two kinds of explicit traveling wave solutions are presented. Examples are given to show the influences of pre-stretch and viscosity on the wave shape and wave velocity. It is shown that pre-stretch could be an effective method for modulating the two types of waves. In addition, such waves may be utilized to measure the viscosity coefficient of the material. The competition between the effects of pre-stretch and viscosity on the kink and kink-like waves is also revealed.

  9. The effects of static stretching on speed and agility: One or multiple repetition protocols?

    Science.gov (United States)

    Avloniti, Alexandra; Chatzinikolaou, Athanasios; Fatouros, Ioannis G; Protopapa, Maria; Athanailidis, Ioannis; Avloniti, Christina; Leontsini, Diamanda; Mavropalias, George; Jamurtas, Athanasios Z

    2016-01-01

    Although static stretching (SS) is utilized during warm-up before training and competition, the results about its effects on performance remain controversial. We examined whether performing a stretch of short-to-moderate duration (agility performance from the effect which is produced while performing the same stretch in multiple repetitions of the same total duration. According to a repeated measurement design, 40 trained males were randomly assigned to either (1) a single repetition group or (2) a multiple repetition group. The participants in each group performed five trials: a control trial (no stretches were performed) and four experimental trials of SS protocols consisting of five exercises performed at either 20 sec (2 × 10 in the second group), 30 sec (3 × 10 in the second group), 40 sec (4 × 10 in the second group) or 60 sec (6 × 10 in the second group) of total duration. A two-way repeated measures analysis of variance showed that the participants in both group improved their speed performance in response to the 20-sec trial, whereas agility remained unaffected. Data analysis also revealed that the repetition number did not affect speed and agility performance. These data suggest that SS of short duration (agility performance. Moreover, the effects of SS protocols are related to the total duration of each exercise and not to the number of repetitions in which each exercise is performed.

  10. The Hydrodynamics of DNA Electrophoretic Stretch and Relaxation in a Polymer Solution

    Science.gov (United States)

    Ferree, Sean; Blanch, Harvey W.

    2004-01-01

    Theories of DNA electrophoretic separations generally treat the DNA as a free draining polymer moving in an electric field at a rate that depends on the effective charge density of the molecule. Separations can occur in sieving media ranging from ultradilute polymer solutions to tightly cross-linked gels. It has recently been shown that DNA is not free-draining when both electric and nonelectric forces simultaneously act on the molecule, as occurs when DNA collides with a polymer during electrophoretic separations. Here we show that a semidilute polymer solution screens the hydrodynamic interaction that results from the application of these forces. Fluorescently labeled DNA tethered at one end in a semidilute solution of hydroxyl-ethyl cellulose stretch more in an electric field than they stretch in free solution, and approach free-draining behavior. The steady stretching behavior is predicted without adjustable parameters by a theory developed by Stigter using a hydrodynamic screening length found from effective medium theory. Data on the relaxation of stretched molecules after the electric field is removed agree with the Rouse model prediction, which neglects hydrodynamic interactions. The slowest relaxation time constant, τR, scales with chain length as τR ∼ L1.9±0.17 when analyzed by the data collapse method, and as τR ∼ L2.17±0.17 when analyzed by multiexponential fit. PMID:15240480

  11. Tip opening of premixed bunsen flames: Extinction with negative stretch and local Karlovitz number

    KAUST Repository

    Vu, Tranmanh

    2015-04-01

    The characteristics of tip openings in premixed bunsen flames have been studied experimentally by measuring OH radicals from laser-induced fluorescence and tip curvatures from chemiluminescent images. Results showed that the tip opening occurred at a constant equivalence ratio and was independent of the jet velocity in propane/air mixtures. The observation of a local extinction phenomenon of the negatively stretched flame due to the flame curvature could not be consistently explained based on flame stretch or the Karlovitz number, since they varied appreciably with the jet velocity. The concept of the local Karlovitz number (KaL) was introduced, which is defined as the ratio of the characteristic reaction time in the normal direction for a stretched flame to the characteristic flow time in the tangential direction for the stretched flame. The local Karlovitz number maintained a constant value under tip opening conditions, irrespective of the jet velocity. Tip opening occurred at a reasonably constant local Karlovitz number of about ~1.72 when the nitrogen dilution level in propane and n-butane fuels was varied.

  12. Increased expression of endothelin B receptor in static stretch exposed porcine mitral valve leaflets

    DEFF Research Database (Denmark)

    Pedersen, Lotte Gam; Zhao, J.; Yang, J.

    2007-01-01

    The aim of this study was to evaluate the effect of mechanical stretch on the expression of ET-1 and ETA- and ETB-receptors in porcine mitral valve leaflets. Leaflet segments from 10 porcine mitral valves were exposed to a static stretch load of 1.5 N for 3.5 h in buffer at 37oC together...... with matching control segments. Subsequently, the mRNA expression of ET-1, ETA-R and ETB-R was measured by real-time RT-PCR in the chordal insertion areas. The analyses showed an increased transcription of ETB-receptors in stretch-exposed leaflet segments compared to unstretched segments median 2.23 (quartiles...... 1.37 and 2.70) vs. median 1.56 (quartiles 1.38 and 2.17, P=0.03) whereas the mRNA expression of ETA-receptors (P=0.90) and ET-1 (P=0.51) remained unchanged. Stretch increased the expression of ETB-receptors in porcine mitral valve leaflets. The finding could lead to a better understanding...

  13. A COMPARATIVE STUDY ON EFFECTIVENESS OF STATIC STRETCH AND HOLD RELAX TECHNIQUES OVER HAMSTRING FLEXIBILITY

    Directory of Open Access Journals (Sweden)

    N. Vamsidhar

    2014-12-01

    Full Text Available Background: Flexibility is important in prevention of injury, muscular and postural imbalance more over the Hamstring flexibility has a lion share in sports performances and preventing DOMS. Stretching procedures increases the ROM by embarking on biomechanics and Neurologic and molecular mechanics. Hamstrings, the two joint muscle plays a crucial role in two joints integrity and also spine as they are in closed kinematic chain. The hamstring muscles represent the primary flexors of Knee. Hamstrings tightness results in Limits Knee extension when hip is flexed, Posterior Pelvic tilt, and flatten the lumbar spine. Methods: The subjects selected randomly and divided into two groups (Experimental group and control group.30 samples in One group applied with Static Stretch once a day for 3 repetitions 5 days a week for six weeks and 30 samples in other group applied with Hold relax technique once a day for 4 repetitions 5 days a week for six weeks. The knee joint range of motion was measured at the end of every week with Universal goniometer. Results: By comparing the means of Group – I, given Static Stretch and Group – II, given Hold relax Technique for six weeks implied that there is improvement of flexibility in Group – II and the ‘P’ value < 0.01 shows the difference is highly significant. Conclusion: This study concludes that the hold relax Technique method has proved to be better technique then the static stretch for improving hamstring flexibility.

  14. An automated multidimensional thin film stretching device for the generation of anisotropic polymeric micro- and nanoparticles.

    Science.gov (United States)

    Meyer, Randall A; Meyer, Randall S; Green, Jordan J

    2015-08-01

    Anisotropic polymeric particles are of growing interest for biomaterials applications due to their unique properties. These include the ability for these particles to evade nonspecific cellular uptake and to have enhanced targeted cellular uptake and interaction. One of the most widely used methods for generating anisotropic polymeric particles is the thin film stretching procedure. Despite its theoretical simplicity, this procedure, as it has been implemented to date, can be difficult due to the inconsistent nature of the manual operation of machinery used to stretch the film. We have constructed an automated thin film stretcher for control over biomaterials via thin film stretching in 1D and 2D and as a result, have enabled precise generation of anisotropic polymeric particles. We demonstrate that this device can be utilized to produce anisotropic biodegradable particles of different size, shape, and material consistency. Furthermore, we show that this machine has enabled the scaled up and rapid production of anisotropic polymeric particles, including polymeric microparticles that mimic the shape of red blood cells. Further application of this automated thin film stretching device could allow for significant impact to diverse biomaterial and biomedical applications such as biomimetic particles for immunoengineering and long-circulating particles for controlled release of drugs. © 2015 Wiley Periodicals, Inc.

  15. Computing the stretch factor and maximum detour of paths, trees, and cycles in the normed space

    DEFF Research Database (Denmark)

    Wulff-Nilsen, Christian; Grüne, Ansgar; Klein, Rolf

    2012-01-01

    The stretch factor and maximum detour of a graph G embedded in a metric space measure how well G approximates the minimum complete graph containing G and the metric space, respectively. In this paper we show that computing the stretch factor of a rectilinear path in L 1 plane has a lower bound of Ω......(n log n) in the algebraic computation tree model and describe a worst-case O(σn log 2 n) time algorithm for computing the stretch factor or maximum detour of a path embedded in the plane with a weighted fixed orientation metric defined by σ vectors and a worst-case O(n log d n) time algorithm to d...... generalize the algorithms to compute the stretch factor or maximum detour of trees and cycles in O(σn log d+1 n) time. We also obtain an optimal O(n) time algorithm for computing the maximum detour of a monotone rectilinear path in L 1 plane....

  16. SNR approach for performance evaluation of time-stretching photonic analogue to digital converter system.

    Science.gov (United States)

    Alves, Tiago M F; Cartaxo, Adolfo V T

    2011-01-17

    A semi-analytical simulation method (SASM) is proposed to evaluate the signal-to-noise ratio (SNR) of time stretched signals at the output of photonic analogue-to-digital converter (Ph-ADC) system. Analytical expressions of the signal at Ph-ADC output considering generic electrical signals applied to the electro-optic modulators of the Ph-ADC are derived. The contribution to the total variance of the received signal from the noise introduced by the electrical transmitter and receiver, and by the optical amplifier are derived analytically taking into account the pulsed nature of the optical signal. The proposed SASM shows excellent agreement of SNR estimates with the estimates provided by Monte Carlo simulation. This result is confirmed for variance dominantly imposed by the noise introduced by the electrical transmitter, by the optical amplifier and by the electrical receiver. A simplified approach is also proposed and compared with previous work. It is shown that mean power estimates obtained from this simplified approach are valid while the modulator is operating in the linear region and the signal is not affected by the frequency response of the electrical receiver filter. Additionally, it is concluded that the estimates of the noise variance due to the electrical transmitter are acceptable when a small signal analysis of noise along the Ph-ADC is valid.

  17. Proprioceptive localization of the hand changes when skin stretch around the elbow is manipulated

    Directory of Open Access Journals (Sweden)

    Irene A. Kuling

    2016-10-01

    Full Text Available Cutaneous information has been shown to influence proprioceptive position sense when subjects had to judge or match the posture of their limbs. In the present study, we tested whether cutaneous information also affects proprioceptive localization of the hand when moving it to a target. In an explorative study, we manipulated the skin stretch around the elbow by attaching elastic sports tape to one side of the arm. Subjects were asked to move the unseen manipulated arm to visually presented targets. We found that the tape induced a significant shift of the end-points of these hand movements. Surprisingly, this shift corresponded with an increase in elbow extension, irrespective of the side of the arm that was taped. A control experiment showed that this cannot be explained by how the skin stretches, because the skin near the elbow stretches to a similar extent on the inside and outside of the arm when the elbow angle increases and decreases, respectively. A second control experiment reproduced and extended the results of the main experiment for tape on the inside of the arm, and showed that the asymmetry was not just a consequence of the tape originally being applied slightly differently to the outside of the arm. However, the way in which the tape was applied does appear to matter, because applying the tape in the same way to the outside of the arm as to the inside of the arm influenced different subjects quite differently, suggesting that the relationship between skin stretch and sensed limb posture is quite complex. We conclude that the way the skin is stretched during a goal-directed movement provides information that helps guide the hand towards the target.

  18. AI-augmented time stretch microscopy

    Science.gov (United States)

    Mahjoubfar, Ata; Chen, Claire L.; Lin, Jiahao; Jalali, Bahram

    2017-02-01

    Cell reagents used in biomedical analysis often change behavior of the cells that they are attached to, inhibiting their native signaling. On the other hand, label-free cell analysis techniques have long been viewed as challenging either due to insufficient accuracy by limited features, or because of low throughput as a sacrifice of improved precision. We present a recently developed artificial-intelligence augmented microscope, which builds upon high-throughput time stretch quantitative phase imaging (TS-QPI) and deep learning to perform label-free cell classification with record high-accuracy. Our system captures quantitative optical phase and intensity images simultaneously by frequency multiplexing, extracts multiple biophysical features of the individual cells from these images fused, and feeds these features into a supervised machine learning model for classification. The enhanced performance of our system compared to other label-free assays is demonstrated by classification of white blood T-cells versus colon cancer cells and lipid accumulating algal strains for biofuel production, which is as much as five-fold reduction in inaccuracy. This system obtains the accuracy required in practical applications such as personalized drug development, while the cells remain intact and the throughput is not sacrificed. Here, we introduce a data acquisition scheme based on quadrature phase demodulation that enables interruptionless storage of TS-QPI cell images. Our proof of principle demonstration is capable of saving 40 TB of cell images in about four hours, i.e. pictures of every single cell in 10 mL of a sample.

  19. GRAVITATIONALLY UNSTABLE FLAMES: RAYLEIGH-TAYLOR STRETCHING VERSUS TURBULENT WRINKLING

    International Nuclear Information System (INIS)

    Hicks, E. P.; Rosner, R.

    2013-01-01

    In this paper, we provide support for the Rayleigh-Taylor-(RT)-based subgrid model used in full-star simulations of deflagrations in Type Ia supernovae explosions. We use the results of a parameter study of two-dimensional direct numerical simulations of an RT unstable model flame to distinguish between the two main types of subgrid models (RT or turbulence dominated) in the flamelet regime. First, we give scalings for the turbulent flame speed, the Reynolds number, the viscous scale, and the size of the burning region as the non-dimensional gravity (G) is varied. The flame speed is well predicted by an RT-based flame speed model. Next, the above scalings are used to calculate the Karlovitz number (Ka) and to discuss appropriate combustion regimes. No transition to thin reaction zones is seen at Ka = 1, although such a transition is expected by turbulence-dominated subgrid models. Finally, we confirm a basic physical premise of the RT subgrid model, namely, that the flame is fractal, and thus self-similar. By modeling the turbulent flame speed, we demonstrate that it is affected more by large-scale RT stretching than by small-scale turbulent wrinkling. In this way, the RT instability controls the flame directly from the large scales. Overall, these results support the RT subgrid model.

  20. Effects of Static Stretching and Playing Soccer on Knee Laxity

    NARCIS (Netherlands)

    Baumgart, Christian; Gokeler, Alli; Donath, Lars; Hoppe, Matthias W.; Freiwald, Juergen

    2015-01-01

    Objective: This study investigated exercise-induced effects of static stretching and playing soccer on anterior tibial translation (ATT) of the knee joint. Design: Randomized controlled trial. Setting: University biomechanics laboratory. Participants: Thirty-one athletes were randomly assigned into

  1. Show-Bix &

    DEFF Research Database (Denmark)

    2014-01-01

    The anti-reenactment 'Show-Bix &' consists of 5 dias projectors, a dial phone, quintophonic sound, and interactive elements. A responsive interface will enable the Dias projectors to show copies of original dias slides from the Show-Bix piece ”March på Stedet”, 265 images in total. The copies are...

  2. Titin force enhancement following active stretch of skinned skeletal muscle fibres.

    Science.gov (United States)

    Powers, Krysta; Joumaa, Venus; Jinha, Azim; Moo, Eng Kuan; Smith, Ian Curtis; Nishikawa, Kiisa; Herzog, Walter

    2017-09-01

    In actively stretched skeletal muscle sarcomeres, titin-based force is enhanced, increasing the stiffness of active sarcomeres. Titin force enhancement in sarcomeres is vastly reduced in mdm , a genetic mutation with a deletion in titin. Whether loss of titin force enhancement is associated with compensatory mechanisms at higher structural levels of organization, such as single fibres or entire muscles, is unclear. The aim of this study was to determine whether mechanical deficiencies in titin force enhancement are also observed at the fibre level, and whether mechanisms compensate for the loss of titin force enhancement. Single skinned fibres from control and mutant mice were stretched actively and passively beyond filament overlap to observe titin-based force. Mutant fibres generated lower contractile stress (force divided by cross-sectional area) than control fibres. Titin force enhancement was observed in control fibres stretched beyond filament overlap, but was overshadowed in mutant fibres by an abundance of collagen and high variability in mechanics. However, titin force enhancement could be measured in all control fibres and most mutant fibres following short stretches, accounting for ∼25% of the total stress following active stretch. Our results show that the partial loss of titin force enhancement in myofibrils is not preserved in all mutant fibres and this mutation likely affects fibres differentially within a muscle. An increase in collagen helps to reestablish total force at long sarcomere lengths with the loss in titin force enhancement in some mutant fibres, increasing the overall strength of mutant fibres. © 2017. Published by The Company of Biologists Ltd.

  3. Acute effect of static stretching on muscle force in older women

    Directory of Open Access Journals (Sweden)

    André Luiz Demantova Gurjão

    2010-04-01

    Full Text Available The objective of this study was to investigate the acute effect of static stretching on the peak rate of force development (PRFD and maximum voluntary contraction (MVC in older women. Ten women (68.5 ± 7.0 years; 70.9 ± 8.1 kg; 159.4 ± 6.0 cm; body mass index: 28.0 ± 3.8 kg/m2 were studied. MVC and PRFD were determined by leg press exercise before and after the control or stretching condition (three sets of 30 seconds of static stretching of the quadriceps on two different days (interval of 24 hours. PRFD was determined as the steepest slope of the curve, calculated within regular windows of 20 milliseconds (∆force/∆time for the first 200 milliseconds after the onset of contraction. MVC was determined as the highest value recorded in each set. Only one condition was tested on each day and the order of application of each condition was determined randomly. The stretching intensity was evaluated by the muscle pain threshold. Four post-condition assessments (post-treatment, 10, 20, and 30 minutes were performed to monitor muscle strength. ANCOVA 2x5, followed by the Scheffé post-hoc test, showed no significant interactions between conditions vs. times (P > 0.05 for PRFD or MVC. In conclusion, acute bouts of static stretching of the quadriceps femoris do not affect the ability of rapid and maximum muscle force production in older women.

  4. Development of Aluminum-Lithium 2195 Gores by the Stretch Forming Process

    Science.gov (United States)

    Volz, M. P.; Chen, P. S.; Gorti, S.; Salvail, P.

    2014-01-01

    Aluminum-Lithium alloy 2195 exhibits higher mechanical properties and lower density than aluminum alloy 2219, which is the current baseline material for Space Launch System (SLS) cryogenic tank components. Replacement of Al 2219 with Al-Li 2195 would result in substantial weight savings, as was the case when this replacement was made on the shuttle external tank. A key component of cryogenic tanks are the gores, which are welded together to make the rounded ends of the tanks. The required thicknesses of these gores depend on the specific SLS configuration and may exceed the current experience base in the manufacture of such gores by the stretch forming process. Here we describe the steps taken to enhance the formability of Al-Li 2195 by optimizing the heat treatment and stretch forming processes for gore thicknesses up to 0.75", which envelopes the maximum expected gore thicknesses for SLS tanks. An annealing treatment, developed at Marshall Space Flight Center, increased the forming range and strain hardening exponent of Al-Li 2195 plates. Using this annealing treatment, one 0.525" thick and two 0.75" thick gores were manufactured by the stretch forming process. The annealing treatment enabled the stretch forming of the largest ever cross sectional area (thickness x width) of an Al-Li 2195 plate achieved by the manufacturer. Mechanical testing of the gores showed greater than expected ultimate tensile strength, yield strength, modulus, and elongation values. The gores also exhibited acceptable fracture toughness at room and LN2 temperatures. All of the measured data indicate that the stretch formed gores have sufficient material properties to be used in flight domes.

  5. Stretch reflex excitability of the anti-gravity ankle extensor muscle in elderly humans.

    Science.gov (United States)

    Kawashima, N; Nakazawa, K; Yamamoto, S-I; Nozaki, D; Akai, M; Yano, H

    2004-01-01

    To examine whether the stretch reflex excitability of the soleus muscle changes with age, stretch reflexes at rest (REST) and during weak voluntary contractions (ACT) were elicited in 18 older and 14 younger subjects. The amplitude of the stretch reflex responses and gain, defined as the gradient of the regression line for the relation between stretch reflex responses against the angular velocity of the applied perturbation, were evaluated in each short-latency (M1) and two long-latency components (M2 and M3). It was found that in the older group, both the amplitude and gain of the M1 component did not change from the REST to the ACT conditions, whereas in the younger group both variables significantly increased from the REST to ACT conditions. The latency of the M1 component was significantly shorter under the REST condition (older vs. younger: 51.8 +/- 7.37 vs. 55.1 +/- 8.69 ms), while no group differences were found in those variables under the ACT condition, suggesting that the muscle-tendon complexes of SOL muscles of the older subjects were less elastic and had less slack, probably due to age-related histochemical alterations. Further, the Hoffman reflex (H-reflex), elicited during the REST condition in 10 older and 11 younger subjects showed no significant differences, suggesting that the soleus motoneuron response to the Ia input was comparable between the two subject groups. The histochemical alterations occurring with the ageing process might augment the short-latency stretch reflex in the SOL muscle without enhancement of motoneuronal excitability, and this effect might be masked when the muscle is voluntarily activated.

  6. The effects of stretching exercise for upper trapezius on the asymmetric rate of bite force.

    Science.gov (United States)

    Lee, Bomjin; Lee, Joongsook; Yang, Jeongok; Heo, Kwangjin; Hwang, Hojin; Kim, Boyoung; Han, Dongwook

    2015-07-01

    [Purpose] The purpose of this study was to observe the effects of stretching the upper trapezius muscle on the asymmetric rate of bite force. [Subjects] Forty-seven female university students who had all their original teeth, had no disorders in the temporomandibular joints, and had never worn braces; participated in this study. [Methods] An occlusometer was used to measure biting forces. Subsequently, stretching exercises of the upper trapezius were performed. The subjects were divided into 3 groups at the start of the testing: the asymmetric rate of the first group was less than 10%; the asymmetric rate of the second group was between 10% and 20%; and the asymmetric rate of the third group was more than 20%. The stretching exercises were done on the dominant side of the upper trapezius. [Results] After the stretching exercises of the upper trapezius, the results showed that for the first group, whose asymmetric rate of biting force was less than 10%, there was a significant increase in asymmetric rate (from 5.1% to 10.3%). For the second group, whose asymmetric rate of biting force was measured to be between 10% and 20%, the asymmetric rate decreased from 14.7% to 14.3%, but the change was not statistically significant. For the third group, whose asymmetric rate of biting force was more than 20%, there was a significant decrease in asymmetric rate (from 27.8% to 12.6%). [Conclusion] We concluded that stretching exercises of the upper trapezius muscle had a direct effect on the asymmetric rate of biting force.

  7. Effect of one stretch a week applied to the immobilized soleus muscle on rat muscle fiber morphology

    Directory of Open Access Journals (Sweden)

    Gomes A.R.S.

    2004-01-01

    Full Text Available We determined the effect of stretching applied once a week to the soleus muscle immobilized in the shortened position on muscle fiber morphology. Twenty-six male Wistar rats weighing 269 ± 26 g were divided into three groups. Group I, the left soleus was immobilized in the shortened position for 3 weeks; group II, the soleus was immobilized in the shortened position and stretched once a week for 3 weeks; group III, the soleus was submitted only to stretching once a week for 3 weeks. The medial part of the soleus muscle was frozen for histology and muscle fiber area evaluation and the lateral part was used for the determination of number and length of serial sarcomeres. Soleus muscle submitted only to immobilization showed a reduction in weight (44 ± 6%, P = 0.002, in serial sarcomere number (23 ± 15% and in cross-sectional area of the fibers (37 ± 31%, P < 0.001 compared to the contralateral muscles. The muscle that was immobilized and stretched showed less muscle fiber atrophy than the muscles only immobilized (P < 0.05. Surprisingly, in the muscles submitted only to stretching, fiber area was decreased compared to the contralateral muscle (2548 ± 659 vs 2961 ± 806 µm², respectively, P < 0.05. In conclusion, stretching applied once a week for 40 min to the soleus muscle immobilized in the shortened position was not sufficient to prevent the reduction of muscle weight and of serial sarcomere number, but provided significant protection against muscle fiber atrophy. In contrast, stretching normal muscles once a week caused a reduction in muscle fiber area.

  8. Effects of right atrial stretch on plasma renin activity.

    Science.gov (United States)

    Annat, G; Grandjean, B; Vincent, M; Jarsaillon, E; Sassard, J

    1976-04-01

    In anaesthetized dog, right atrial stretch leads in the first five minutes to a decrease in plasma renin activity, when measured in inferior vena cava just above the renal veins. Bilateral cervical vagotomy increases plasma renin activity. After vagotomy, atrial stretch no longer has any effect on plasma renin activity. The results support the hypothesis of a control of renin secretion originating from atrial volume receptors.

  9. Equibiaxial cyclic stretch stimulates fibroblasts to rapidly remodel fibrin.

    Science.gov (United States)

    Balestrini, Jenna Leigh; Billiar, Kristen Lawrence

    2006-01-01

    Understanding the effects of the mechanical environment on wound healing is critical for developing more effective treatments to reduce scar formation and contracture. The aim of this study was to investigate the effects of dynamic mechanical stretch on cell-mediated early wound remodeling independent of matrix alignment which obscures more subtle remodeling mechanisms. Cyclic equibiaxial stretch (16% stretch at 0.2 Hz) was applied to fibroblast-populated fibrin gel in vitro wound models for eight days. Compaction, density, tensile strength, and collagen content were quantified as functional measures of remodeling. Stretched samples were approximately ten times stronger, eight-fold more dense, and eight times thinner than statically cultured samples. These changes were accompanied by a 15% increase in net collagen but no significant differences in cell number or viability. When collagen crosslinking was inhibited in stretched samples, the extensibility increased and the strength decreased. The apparent weakening was due to a reduction in compaction rather than a decrease in ability of the tissue to withstand tensile forces. Interestingly, inhibiting collagen crosslinking had no measurable effects on the statically cultured samples. These results indicate that amplified cell-mediated compaction and even a slight addition in collagen content play substantial roles in mechanically induced wound strengthening. These findings increase our understanding of how mechanical forces guide the healing response in skin, and the methods employed in this study may also prove valuable tools for investigating stretch-induced remodeling of other planar connective tissues and for creating mechanically robust engineered tissues.

  10. Effects of Stretching Exercise on Heart Rate Variability During Pregnancy.

    Science.gov (United States)

    Logan, Jeongok G; Yeo, SeonAe

    Little evidence exists for effects of low-intensity exercises such as stretching on cardiovascular health in pregnant women. Our aim was to evaluate the effect of a 20-minute stretching exercise on heart rate variability (HRV), blood pressure (BP), and heart rate (HR) in healthy pregnant women. In 15 pregnant women with a mean (SD) age of 29.47 (4.07) years and mean (SD) gestational weeks of 26.53 (8.35), HRV, and BP were measured before and after the 20-minute stretching exercise. Compared with before the stretching exercise, standard deviation of the normal-to-normal intervals, total variability of heart rate, increased by 7.40 milliseconds (t = -2.31, P = .04) and root mean square of successive differences, a surrogate measure of parasympathetic outflow, also increased by 11.68 milliseconds (Z = -2.04, P = .04) after the stretching exercise. Diastolic BP and HR decreased by 2.13 mm Hg (t = 1.93, P = .07) and 3.31 bpm (t = 2.17, P = .05), respectively, but they did not reach statistical significance. These preliminary data suggest that 20 minutes of stretching exercise may promote cardiovascular health by attenuating the loss of parasympathetic tone associated with pregnancy.

  11. [Sciatica. From stretch rack to microdiscectomy].

    Science.gov (United States)

    Gruber, P; Böni, T

    2015-12-01

    In ancient times as well as in the Middle Ages treatment options for discogenic nerve compression syndrome were limited and usually not very specific because of low anatomical and pathophysiological knowledge. The stretch rack (scamnum Hippocratis) was particularly prominent but was widely used as a therapeutic device for very different spinal disorders. Since the beginning of the nineteenth century anatomical knowledge increased and the advances in the fields of asepsis, anesthesia and surgery resulted in an increase in surgical interventions on the spine. In 1908 the first successful lumbar discectomy was initiated and performed by the German neurologist Heinrich O. Oppenheim (1858-1919) and the surgeon Fedor Krause (1857-1937); however, neither recognized the true pathological condition of discogenic nerve compression syndrome. With the landmark report in the New England Journal of Medicine in 1934, the two American surgeons William Jason Mixter (1880-1958) and Joseph Seaton Barr (1901-1963) finally clarified the pathomechanism of lumbar disc herniation and furthermore, propagated discectomy as the standard therapy. Since then interventions on intervertebral discs rapidly increased and the treatment options for lumbar disc surgery quickly evolved. The surgical procedures changed over time and were continuously being refined. In the late 1960s the surgical microscope was introduced for spinal surgery by the work of the famous neurosurgeon Mahmut Gazi Yasargil and his colleague Wolfhard Caspar and so-called microdiscectomy was introduced. Besides open discectomy other interventional techniques were developed to overcome the side effects of surgical procedures. In 1964 the American orthopedic surgeon Lyman Smith (1912-1991) introduced chemonucleolysis, a minimally invasive technique consisting only of a cannula and the proteolytic enzyme chymopapain, which is injected into the disc compartment to dissolve the displaced disc material. In 1975 the Japanese orthopedic

  12. The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects.

    LENUS (Irish Health Repository)

    O'Sullivan, Kieran

    2009-01-01

    BACKGROUND: Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. METHODS: A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM). 18 previously injured individuals and 18 uninjured controls participated. On both days, four measurements of PKE ROM were recorded: (1) at baseline; (2) after warm-up; (3) after stretch (static or dynamic) and (4) after a 15-minute rest. Participants carried out both static and dynamic stretches, but on different days. Data were analysed using Anova. RESULTS: Across both groups, there was a significant main effect for time (p < 0.001). PKE ROM significantly increased with warm-up (p < 0.001). From warm-up, PKE ROM further increased with static stretching (p = 0.04) but significantly decreased after dynamic stretching (p = 0.013). The increased flexibility after warm-up and static stretching reduced significantly (p < 0.001) after 15 minutes of rest, but remained significantly greater than at baseline (p < 0.001). Between groups, there was no main effect for group (p = 0.462), with no difference in mean PKE ROM values at any individual stage of the protocol (p > 0.05). Using ANCOVA to adjust for the non-significant (p = 0.141) baseline difference between groups, the previously injured group demonstrated a greater response to warm-up and static stretching, however this was not statistically significant (p = 0.05). CONCLUSION: Warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not, in agreement with previous findings on uninjured controls. The effect of warm-up and static stretching on flexibility was greater in those with reduced

  13. Cell classification using big data analytics plus time stretch imaging (Conference Presentation)

    Science.gov (United States)

    Jalali, Bahram; Chen, Claire L.; Mahjoubfar, Ata

    2016-09-01

    We show that blood cells can be classified with high accuracy and high throughput by combining machine learning with time stretch quantitative phase imaging. Our diagnostic system captures quantitative phase images in a flow microscope at millions of frames per second and extracts multiple biophysical features from individual cells including morphological characteristics, light absorption and scattering parameters, and protein concentration. These parameters form a hyperdimensional feature space in which supervised learning and cell classification is performed. We show binary classification of T-cells against colon cancer cells, as well classification of algae cell strains with high and low lipid content. The label-free screening averts the negative impact of staining reagents on cellular viability or cell signaling. The combination of time stretch machine vision and learning offers unprecedented cell analysis capabilities for cancer diagnostics, drug development and liquid biopsy for personalized genomics.

  14. EFFECTIVENESS OF PNF STRETCHING VERSUS STATIC STRETCHING ON PAIN AND HAMSTRING FLEXIBILITY FOLLOWING MOIST HEAT IN INDIVIDUALS WITH KNEE OSTEOARTHRITIS

    OpenAIRE

    Meena .V; Shanthi .C; Madhavi .K

    2016-01-01

    Background: Osteoarthritis (OA) is a degenerative joint disease and one of the major public health problem that causesfunctional impairment and reduced quality of life. To compare the effectiveness of PNF Hold relax stretching versus Static stretching on pain and flexibility of hamstring following moist heat in individuals with knee osteoarthritis. Hamstring tightness is the major problem in knee osteoarthritis individuals. Therefore the need of study is comparing the effectiveness of PNF Hol...

  15. The effect of warm-up, static stretching and dynamic stretching on hamstring flexibility in previously injured subjects

    Directory of Open Access Journals (Sweden)

    Murray Elaine

    2009-04-01

    Full Text Available Abstract Background Warm-up and stretching are suggested to increase hamstring flexibility and reduce the risk of injury. This study examined the short-term effects of warm-up, static stretching and dynamic stretching on hamstring flexibility in individuals with previous hamstring injury and uninjured controls. Methods A randomised crossover study design, over 2 separate days. Hamstring flexibility was assessed using passive knee extension range of motion (PKE ROM. 18 previously injured individuals and 18 uninjured controls participated. On both days, four measurements of PKE ROM were recorded: (1 at baseline; (2 after warm-up; (3 after stretch (static or dynamic and (4 after a 15-minute rest. Participants carried out both static and dynamic stretches, but on different days. Data were analysed using Anova. Results Across both groups, there was a significant main effect for time (p 0.05. Using ANCOVA to adjust for the non-significant (p = 0.141 baseline difference between groups, the previously injured group demonstrated a greater response to warm-up and static stretching, however this was not statistically significant (p = 0.05. Conclusion Warm-up significantly increased hamstring flexibility. Static stretching also increased hamstring flexibility, whereas dynamic did not, in agreement with previous findings on uninjured controls. The effect of warm-up and static stretching on flexibility was greater in those with reduced flexibility post-injury, but this did not reach statistical significance. Further prospective research is required to validate the hypothesis that increased flexibility improves outcomes. Trial Registration ACTRN12608000638336

  16. Cardiovascular Responses to Skeletal Muscle Stretching: "Stretching" the Truth or a New Exercise Paradigm for Cardiovascular Medicine?

    Science.gov (United States)

    Kruse, Nicholas T; Scheuermann, Barry W

    2017-12-01

    Stretching is commonly prescribed with the intended purpose of increasing range of motion, enhancing muscular coordination, and preventing prolonged immobilization induced by aging or a sedentary lifestyle. Emerging evidence suggests that acute or long-term stretching exercise may modulate a variety of cardiovascular responses. Specifically, at the onset of stretch, the mechanical deformation of the vascular bed coupled with stimulation of group III muscle afferent fibers initiates a cascade of events resulting in both peripheral vasodilation and a heart rate-driven increase in cardiac output, blood pressure, and muscle blood flow. This potential to increase shear stress and blood flow without the use of excessive muscle energy expenditure may hold important implications for future therapeutic vascular medicine and cardiac health. However, the idea that a cardiovascular component may be involved in human skeletal muscle stretching is relatively new. Therefore, the primary intent of this review is to highlight topics related to skeletal muscle stretching and cardiovascular regulation and function. The current evidence suggests that acute stretching causes a significant macro- and microcirculatory event that alters blood flow and the relationship between oxygen availability and oxygen utilization. These acute vascular changes if performed chronically may result in improved endothelial function, improved arterial blood vessel stiffness, and/or reduced blood pressure. Although several mechanisms have been postulated, an increased nitric oxide bioavailability has been highlighted as one promising candidate for the improvement in vessel function with stretching. Collectively, the evidence provided in this review suggests that stretching acutely or long term may serve as a novel and alternative low intensity therapeutic intervention capable of improving several parameters of vascular function.

  17. Effectiveness of different exercises and stretching physiotherapy on pain and movement in patellofemoral pain syndrome: a randomized controlled trial.

    Science.gov (United States)

    Moyano, F Revelles; Valenza, M C; Martin, L Martin; Caballero, Y Castellote; Gonzalez-Jimenez, E; Demet, G Valenza

    2013-05-01

    To compare the effectiveness of proprioceptive neuromuscular facilitation combined with exercise, classic stretching physiotherapy intervention, and educational intervention at improving patient function and pain in patients with patellofemoral pain syndrome. Randomized, controlled, blind trial over four months. Urban population, Spain. Patients undergoing primary care for retropatellar pain. Subjects were allocated on three different treatment options: a proprioceptive neuromuscular facilitation and aerobic exercise group, a classic stretching group, and a control treatment were applied over four months under the supervision of a physiotherapist. Knee Society Score, pain reported (Visual analogue scale) and knee range of motion. Assessments were completed at baseline and after four months. 74 patients were enrolled in the study and distributed between groups. Both the proprioceptive neuromuscular facilitation and classic stretching group showed significant changes in all variables after four months intervention (p stretching group vs. proprioceptive neuromuscular facilitation group vs. control group) at four months was -24.05 (95% confidence interval (CI) -30.19, -17.90), p ≤ 0.001; vs. -39.03 (95% confidence interval (CI) -42.5, -35.5), p ≤ 0.001; vs. -0.238 (95% confidence interval (CI) -1.2, 0.726), p = 0.621, respectively. A proprioceptive neuromuscular facilitation intervention protocol combined with aerobic exercise showed a better outcome than a classic stretching protocol after four months.

  18. DNA-wrapped carbon nanotubes aligned in stretched gelatin films: Polarized resonance Raman and absorption spectroscopy study

    Science.gov (United States)

    Glamazda, A. Yu.; Plokhotnichenko, A. M.; Leontiev, V. S.; Karachevtsev, V. A.

    2017-09-01

    We present the study of DNA-wrapped single-walled carbon nanotubes (SWNTs) embedded in the stretched gelatin film by the polarized resonance Raman spectroscopy and visible-NIR optical absorption. The polarized dependent absorption spectra taken along and normal to the stretching direction demonstrate a comparatively high degree of the alignment of isolated SWNTs in the gelatin matrix. The analysis of Raman spectra of isolated SWNTs in the gelatin stretched films showed that the degree of the alignment of carbon nanotubes along the stretching direction is about 62%. The dependence of the peak position of G+-band in Raman spectra on the polarization angle θ between the polarization of the incident light and the direction of the stretching of films was revealed. This shift is explained by the different polarization dependence of the most intensive A and E1 symmetry modes within the G+-band. The performed studies of embedded DNA-wrapped nanotubes in the gelatin film show the simple method for obtaining the controlled ordered biocompatible nanotubes inside a polymer matrix. It can be used for manufacturing sizable flexible self-transparent films with integrated nanoelectrodes.

  19. Effects of Static Stretching and Playing Soccer on Knee Laxity.

    Science.gov (United States)

    Baumgart, Christian; Gokeler, Alli; Donath, Lars; Hoppe, Matthias W; Freiwald, Jürgen

    2015-11-01

    This study investigated exercise-induced effects of static stretching and playing soccer on anterior tibial translation (ATT) of the knee joint. Randomized controlled trial. University biomechanics laboratory. Thirty-one athletes were randomly assigned into a stretching (26.9 ± 6.2 years, 1.77 ± 0.09 m, 67.9 ± 10.7 kg) and a control group (27.9 ± 7.4 years, 1.75 ± 0.08 m, 72.0 ± 14.9 kg). Thirty-one amateur soccer players in an additional soccer group (25.1 ± 5.6 years, 1.74 ± 0.10 m, 71.8 ± 14.8 kg). All participants had no history of knee injury requiring surgery and any previous knee ligament or cartilage injury. The stretching group performed 4 different static stretching exercises with a duration of 2 × 20 seconds interspersed with breaks of 10 seconds. The soccer group completed a 90-minute soccer-specific training program. The control group did not perform any physical activity for approximately 30 minutes. Anterior tibial translation was measured with the KT-1000 knee arthrometer at forces of 67 N, 89 N, and maximal manual force (Max) before and after the intervention. There was a significant increase in ATT after static stretching and playing soccer at all applied forces. Maximal manual testing revealed a mean increase of ATT after static stretching of 2.1 ± 1.6 mm (P static stretching at 67 and 89 N is significantly higher than in controls. At maximum manual testing, significant differences were evident between all groups. Static stretching and playing soccer increase ATT and may consequently influence mechanical factors of the anterior cruciate ligament. The ATT increase after static stretching was greater than after playing soccer. The observed increase in ATT after static stretching and playing soccer may be associated with changes in kinesthetic perception and sensorimotor control, activation of muscles, joint stability, overall performance, and higher injury risk.

  20. Expression and proliferation profiles of PKC, JNK and p38MAPK in physiologically stretched human bladder smooth muscle cells

    International Nuclear Information System (INIS)

    Wazir, Romel; Luo, De-Yi; Dai, Yi; Yue, Xuan; Tian, Ye; Wang, Kun-Jie

    2013-01-01

    Highlights: •Stretch induces proliferation in human bladder smooth muscle cells (HBSMC). •5% Equibiaxial elongation produces maximum proliferation. •Physiologic stretch decreases apoptotic cell death. •PKC is involved in functional modulation of bladder. •JNK and p38 are not involved in proliferating HBSMC. -- Abstract: Objective: To determine protein kinase C (PKC), c-Jun NH2-Terminal Kinase (JNK) and P38 mitogen-activated protein kinases (p38MAPK) expression levels and effects of their respective inhibitors on proliferation of human bladder smooth muscle cells (HBSMCs) when physiologically stretched in vitro. Materials and methods: HBSMCs were grown on silicone membrane and stretch was applied under varying conditions; (equibiaxial elongation: 2.5%, 5%, 10%, 15%, 20%, 25%), (frequency: 0.05, 0.1, 0.2, 0.5, 1 Hz). Optimal physiological stretch was established by assessing proliferation with 5-Bromo-2-deoxyuridine (BrdU) assay and flow cytometry. PKC, JNK and p38 expression levels were analyzed by Western blot. Specificity was maintained by employing specific inhibitors; (GF109203X for PKC, SP600125 for JNK and SB203580 for p38MAPK), in some experiments. Results: Optimum proliferation was observed at 5% equibiaxial stretch (BrdU: 0.837 ± 0.026 (control) to 1.462 ± 0.023)%, (P 0.05 SP600125) and (1.461 ± 0.01, P > 0.05 SB203580). These findings show that mechanical stretch can promote magnitude-dependent proliferative modulation through PKC and possibly JNK but not via p38MAPK in hBSMCs

  1. Cyclic stretch induces upregulation of endothelin-1 with keratinocytes in vitro: Possible role in mechanical stress-induced hyperpigmentation

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, Masakazu, E-mail: masakazukurita@gmail.com [Department of Plastic Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka-shi, Tokyo 181-8611 (Japan); Okazaki, Mutsumi [Department of Plastic and Reconstructive Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510 (Japan); Fujino, Takashi [Department of Pathology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka-shi, Tokyo 181-8611 (Japan); Takushima, Akihiko; Harii, Kiyonori [Department of Plastic Surgery, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka-shi, Tokyo 181-8611 (Japan)

    2011-05-27

    Highlights: {yields} Influence of cyclic stretch on melanogenetic paracrine cytokines was investigated. {yields} Keratinocyte-derived endothelin-1 was upregulated with cyclic stretch. {yields} Degree of upregulation increases dose-dependently. {yields} This upregulation possibly plays a role in the pathogenesis of pigmented disorders. -- Abstract: The aim of this study was to investigate the possible pathological relation between mechanical stress and hyperpigmentation. We did this by investigating the influence of cyclic stretch on the expression of keratinocyte- and fibroblast-derived melanogenetic paracrine cytokines in vitro. Using primary human keratinocytes and fibroblasts, alterations of mRNA expression of melanogenetic paracrine cytokines due to cyclic stretch were investigated using a real-time polymerase chain reaction (PCR). The cytokines included basic fibroblast growth factor (bFGF), stem cell factor (SCF), granulocyte/macrophage colony-stimulating factor, interleukin-1{alpha}, and endothelin-1 (ET-1) for keratinocytes and bFGF, SCF, and hepatocyte growth factor for fibroblasts. The dose dependence of keratinocyte-derived ET-1 upregulation was further investigated using real-time PCR and an enzyme-linked immunosorbent assay. We also investigated the effects of cyclic stretch on the proliferation and differentiation of keratinocytes. Among the melanogenetic paracrine cytokines investigated, keratinocyte-derived ET-1 was consistently upregulated in all four cell lines. The degree of upregulation increased with the degree of the length and frequency of the stretch; in contrast, cell number and differentiation markers showed no obvious alterations with cyclic stretch. Keratinocyte-derived ET-1 upregulation possibly plays a significant role in the pathogenesis of pigmented disorders, such as friction melanosis, caused by mechanical stress.

  2. Does adding mobilization to stretching improve outcomes for people with frozen shoulder? A randomized controlled clinical trial.

    Science.gov (United States)

    Çelik, Derya; Kaya Mutlu, Ebru

    2016-08-01

    To assess the effectiveness of joint mobilization combined with stretching exercises in patients with frozen shoulder. A randomized controlled clinical pilot trial. Department of Orthopedics and Traumatology. Thirty patients with frozen shoulder. All participants were randomly assigned to one of two treatment groups: joint mobilization and stretching versus stretching exercises alone. Both groups performed a home exercise program and were treated for six weeks (18 sessions). The primary outcome measures for functional assessment were the Disabilities of the Arm, Shoulder and Hand score and the Constant score. The secondary outcome measures were pain level, as evaluated with a visual analog scale, and range of motion, as measured using a conventional goniometer. Patients were assessed before treatment, at the end of the treatment, and after one year as follow-up. Two-by-two repeated-measures ANOVA with Bonferroni corrections revealed significant increases in abduction (91.9° [CI: 86.1-96.7] to 172.8° [CI: 169.7-175.5]), external rotation (28.1° [CI: 22.2-34.2] to 77.7° [CI: 70.3-83.0]) and Constant score (39.1 [CI: 35.3-42.6] to 80.5 [75.3-86.6]) at the one-year follow-up in the joint mobilization combined with stretching exercise group, whereas the group performing stretching exercise alone did not show such changes. In the treatment of patients with frozen shoulder, joint mobilization combined with stretching exercises is better than stretching exercise alone in terms of external rotation, abduction range of motion and function score. © The Author(s) 2015.

  3. Stretched exponential relaxation in molecular and electronic glasses

    International Nuclear Information System (INIS)

    Phillips, J.C.

    1996-01-01

    Stretched exponential relaxation, exp[-(t/τ) β ], fits many relaxation processes in disordered and quenched electronic and molecular systems, but it is widely believed that this function has no microscopic basis, especially in the case of molecular relaxation. For electronic relaxation the appearance of the stretched exponential is often described in the context of dispersive transport, where β is treated as an adjustable parameter, but in almost all cases it is generally assumed that no microscopic meaning can be assigned to 0 g , a glass transition temperature. We show that for molecular relaxation β(T g ) can be understood, providing that one separates extrinsic and intrinsic effects, and that the intrinsic effects are dominated by two magic numbers, β SR =3/5 for short-range forces, and β K =3/7 for long-range Coulomb forces, as originally observed by Kohlrausch for the decay of residual charge on a Leyden jar. Our mathematical model treats relaxation kinetics using the Lifshitz-Kac-Luttinger diffusion to traps depletion model in a configuration space of effective dimensionality, the latter being determined using axiomatic set theory and Phillips-Thorpe constraint theory. The experiments discussed include ns neutron scattering experiments, particularly those based on neutron spin echoes which measure S(Q, t) directly, and the traditional linear response measurements which span the range from μs to s, as collected and analysed phenomenologically by Angell, Ngai, Boehmer and others. The electronic materials discussed include a-Si:H, granular C 60 , semiconductor nanocrystallites, charge density waves in TaS 3 , spin glasses, and vortex glasses in high-temperature semiconductors. The molecular materials discussed include polymers, network glasses, electrolytes and alcohols, Van der Waals supercooled liquids and glasses, orientational glasses, water, fused salts, and heme proteins. In the intrinsic cases the theory of β(T g ) is often accurate to 2%, which

  4. Stretched-State Excitations with the

    Science.gov (United States)

    Garcia, Luis Alberto Casimiro

    Neutron time-of-fight spectra were obtained for the ^{14}C(p,n) ^{14}N, ^{18 }O(p,n)^{18}F, and ^{30}Si(p,n) ^{30}P reactions at 135 MeV with the beam-swinger system at the Indiana University Cyclotron Facility. Excitation-energy spectra and the differential cross sections for the observed excitations in these reactions were extracted over the momentum transfer range from 0 to 2.7 fm^{-1}. The primary goal of this work was to obtain the strengths and distributions for the "stretched" states. The identification of these states was based on comparisons of the theoretical differential cross sections, performed in a DWIA formalism, with the experimental cross sections. Isospin assignments were based primarily on comparisons of the measured (p,n) and (e,e^') spectroscopic strengths. Candidate (pid_ {5/2},nu{rm p}_sp {3/2}{-1}), J^ pi = 4 ^- T = 0, 1 and 2, 1 hbaromega states, were identified at E_{x} = 8.5, 13.8, 19.5, and 26.7 MeV in the ^{14}C(p,n) ^{14}N reaction, and the corresponding isovector strengths were extracted. The observed 4^--state excitation energies and the strengths are in good agreement with the analog T = 1 and 2, 4^--states observed in the (e,e^') reaction. Large -basis shell-model calculations were found to predict reasonably well the excitation energies; however, these calculations overpredict the strength by a factor of 2, for the T = 1 and 2 components. In the ^{18}O(p,n) ^{18}F reaction at 135 MeV, (pi d_{5/2},nu {rm d}_sp{5/2}{-1 }) 5^+ T = 0 0hbaromega strength was observed, concentrated in a single state, at E_{x} = 1.1 MeV, with 75% of the extreme-single-particle-model (ESPM) strength, in good agreement with a shell-model calculation. No 6^- 1hbaromega strength was observed in this reaction. Candidate (pi {rm d}_{5/2},nu p _sp{3/2}{-1}) J ^pi = 4^- T = 0, 1 and 2, 1hbaromega states, were identified at E_{x} = 3.9, 9.4, 10.2, 11.4, 12.0, 14.4, 15.3, 17.3, 18.0, 19.7, 21.4, and 23.4 MeV. The observed 4^- T = 2 state excitation energies and

  5. Mechanical Stretching Promotes Skin Tissue Regeneration via Enhancing Mesenchymal Stem Cell Homing and Transdifferentiation.

    Science.gov (United States)

    Liang, Xiao; Huang, Xiaolu; Zhou, Yiwen; Jin, Rui; Li, Qingfeng

    2016-07-01

    Skin tissue expansion is a clinical procedure for skin regeneration to reconstruct cutaneous defects that can be accompanied by severe complications. The transplantation of mesenchymal stem cells (MSCs) has been proven effective in promoting skin expansion and helping to ameliorate complications; however, systematic understanding of its mechanism remains unclear. MSCs from luciferase-Tg Lewis rats were intravenously transplanted into a rat tissue expansion model to identify homing and transdifferentiation. To clarify underlying mechanisms, a systematic approach was used to identify the differentially expressed genes between mechanically stretched human MSCs and controls. The biological significance of these changes was analyzed through bioinformatic methods. We further investigated genes and pathways of interest to disclose their potential role in mechanical stretching-induced skin regeneration. Cross sections of skin samples from the expanded group showed significantly more luciferase(+) and stromal cell-derived factor 1α (SDF-1α)(+), luciferase(+)keratin 14(+), and luciferase(+)CD31(+) cells than the control group, indicating MSC transdifferentiation into epidermal basal cells and endothelial cells after SDF-1α-mediated homing. Microarray analysis suggested upregulation of genes related to hypoxia, vascularization, and cell proliferation in the stretched human MSCs. Further investigation showed that the homing of MSCs was blocked by short interfering RNA targeted against matrix metalloproteinase 2, and that mechanical stretching-induced vascular endothelial growth factor A upregulation was related to the Janus kinase/signal transducer and activator of transcription (Jak-STAT) and Wnt signaling pathways. This study determines that mechanical stretching might promote skin regeneration by upregulating MSC expression of genes related to hypoxia, vascularization, and cell proliferation; enhancing transplanted MSC homing to the expanded skin; and

  6. Theoretical evidence for bond stretch isomerism in Grubbs olefin metathesis.

    Science.gov (United States)

    Remya, Premaja R; Suresh, Cherumuttathu H

    2017-07-15

    A comprehensive density functional theory study on the dissociative and associative mechanisms of Grubbs first and second generation olefin metathesis catalysis reveals that ruthenacyclobutane intermediate (RuCB) observed in the Chauvin mechanism is not unique as it can change to a non-metathetic ruthenacyclobutane (RuCB') via the phenomenon of bond stretch isomerism (BSI). RuCB and RuCB' differ mainly in RuC α , RuC β , and C α C β bond lengths of the metallacycle. RuCB is metathesis active due to the agostic type bonding-assisted simultaneous activation of both C α C β bonds, giving hypercoordinate character to C β whereas an absence of such bonding interactions in RuCB' leads to typical CC single bond distances and metathesis inactivity. RuCB and RuCB' are connected by a transition state showing moderate activation barrier. The new mechanistic insights invoking BSI explains the non-preference of associative mechanism and the requirement of bulky ligands in the Grubbs catalyst design. The present study lifts the status of BSI from a concept of largely theoretical interest to a phenomenon of intense importance to describe an eminent catalytic reaction. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  7. Extrinsic stretching narrowing and anterior indentation of the rectosigmoid junction

    International Nuclear Information System (INIS)

    Schulman, A.; Fataar, S.

    1979-01-01

    Thirty-five cases of extrinsic narrowing or anterior indentation of the rectosigmoid junction (RSJ) have been studied. The RSJ lies directly behind the pouch of Douglas which is a favoured site for peritoneal metastasis, abscess and endometriosis. Any space-occupying lesion of sufficient size at this site will indent the anterior aspects of the RSJ. Causes include distension or tumour of the ileum or sigmoid colon, gross ascites (when the patient is erect), and tumours below the pelvic peritonium, such as gynaecological neoplasm and internal iliac artery aneurysm. When a desmoplastic metastasis in the pouch of Douglas infiltrates the outer layers of the RSJ, the fibrosis produces an eccentric shortening on its anterior aspect, which in turn causes a pleating of the mucosa with the folds radiating towards the shortened area. This is also seen with primary pelvic carcinomas directly adherent to the rectum, endometriosis with repeated bleeding and increasing eccentric, submucosal fibrosis, and chronic abscess in the pouch of Douglas. Not all extrinsic narrowing of the RSJ are pathological. One case of anterior indentation followed operation for rectal prolapse. Ten additional cases showed narrowing due to a technical artefact air-distended colon rising into the upper abdomen to cause stretching at the RSJ. As with ascites, this narrowing due to 'high-rise sigmoid' disappeared when the patients became recumbent and the colonic air redistributed. (author)

  8. Stretch-activated cation channel from larval bullfrog skin

    DEFF Research Database (Denmark)

    Hillyard, Stanley D; Willumsen, Niels J; Marrero, Mario B

    2010-01-01

    Cell-attached patches from isolated epithelial cells from larval bullfrog skin revealed a cation channel that was activated by applying suction (-1 kPa to -4.5 kPa) to the pipette. Activation was characterized by an initial large current spike that rapidly attenuated to a stable value and showed...... was markedly reduced with N-methyl-D-glucamide (NMDG)-Cl Ringer's solution in the pipette. Neither amiloride nor ATP, which are known to stimulate an apical cation channel in Ussing chamber preparations of larval frog skin, produced channel activation nor did these compounds affect the response to suction....... Stretch activation was not affected by varying the pipette concentrations of Ca(2+) between 0 mmol l(-1) and 4 mmol l(-1) or by varying pH between 6.8 and 8.0. However, conductance was reduced with 4 mmol l(-1) Ca(2+). Western blot analysis of membrane homogenates from larval bullfrog and larval toad skin...

  9. Modulation of TRESK background K+ channel by membrane stretch.

    Directory of Open Access Journals (Sweden)

    Gerard Callejo

    Full Text Available The two-pore domain K(+ channel TRESK is expressed in dorsal root ganglion and trigeminal sensory neurons where it is a major contributor to background K(+ current. TRESK acts as a break to prevent excessive sensory neuron activation and decreases in its expression or function have been involved in neuronal hyperexcitability after injury/inflammation, migraine or altered sensory perception (tingling, cooling and pungent burning sensations. All these effects have implicated this channel in nociception and mechanotransduction. To determine the role of TRESK in sensory transduction, we studied its sensitivity to changes in membrane tension (stretch in heterologous systems, F-11 cells and trigeminal neurons. Laminar shear stress increased TRESK currents by 22-30%. An increase in membrane tension induced by cell swelling (hypotonic medium produced a reversible elevation of TRESK currents (39.9%. In contrast, cell shrinkage (hypertonic solution produced the opposite effect. Membrane crenators or cup-formers produced equivalent effects. In trigeminal sensory neurons, TRESK channels were mechanically stimulated by negative pressure, which led to a 1.51-fold increase in channel open probability. TRESK-like currents in trigeminal neurons were additively inhibited by arachidonic acid, acidic pH and hypertonic stimulation, conditions usually found after tissue inflammation. Our results show that TRESK is modulated by changes in cell membrane tension and/or cell volume. Several key players released during inflammation or tissue injury could modulate sensory neuron activation through small changes in membrane tension.

  10. Neural effects of muscle stretching on the spinal reflexes in multiple lower-limb muscles.

    Science.gov (United States)

    Masugi, Yohei; Obata, Hiroki; Inoue, Daisuke; Kawashima, Noritaka; Nakazawa, Kimitaka

    2017-01-01

    While previous studies have shown that muscle stretching suppresses monosynaptic spinal reflex excitability in stretched muscles, its effects on non-stretched muscles is still largely unknown. The purpose of this study was to examine the effects of muscle stretching on monosynaptic spinal reflex in non-stretched muscles. Ten healthy male subjects participated in this study. Muscle stretching of the right triceps surae muscle was performed using a motor torque device for 1 minute. Three different dorsiflexion torques (at approximately 5, 10, and 15 Nm) were applied during muscle stretching. Spinal reflexes evoked by transcutaneous spinal cord stimulation were recorded in both the lower-limb muscles before, during, and at 0 and 5 min following muscle stretching. The amplitudes of the spinal reflexes in both the stretched and non-stretched muscles in the right (ipsilateral) leg were smaller during stretching compared to before, and at 0 and 5 min after stretching. Furthermore, the degree of reduction in the amplitude of the spinal reflexes in the right (ipsilateral) leg muscles increased significantly as the dorsiflexion torque (i.e., stretching of the right triceps surae muscles) increased. In contrast, reduction in the amplitude of the spinal reflexes with increasing dorsiflexion torque was not seen in the left (contralateral) leg muscles. Our results clearly indicate that muscle stretching has inhibitory effects on monosynaptic spinal reflexes, not only in stretched muscles, but also in non-stretched muscles of the ipsilateral leg.

  11. The effect of tail stretching on the ionospheric accessibility of relativistic electron beam experiments

    Science.gov (United States)

    Willard, J.; Johnson, J.; Sanchez, E. R.; Kaganovich, I.; Greklek-McKeon, M.; Powis, T.

    2017-12-01

    New accelerator technologies have made it possible to install a lightweight electron beam accelerator onto small to medium satellites. Electron beams fired along the geomagnetic field would be able to carry energy flux into the ionosphere if they were fired into the loss cone, making these particles observable from the ground. Such an experiment would provide a way to accurately map field lines. One of the important challenges to utilizing this concept is understanding accessibility of these electrons to the ionosphere. While relativistic electron beams are generally more stable than lower energy beams, they are more sensitive to the effects of field-line curvature, which can significantly modify the loss cone [Porazik et al., 2014] making accessibility to the ionosphere sensitive to the launch angle with respect to the magnetic field. We examine the loss cone for 1 MeV electrons in a realistic magnetospheric geometry considering, in particular, the role of field-line stretching. To map the loss cone, we consider conservation of the first adiabatic invariant to second order in ρ/L using the asymptotic series derived by Gardner [Phys Fluids, 1966], which is valid on the midnight meridian. We investigate the loss cones for different magnetic field models controlled by a stretching parameter over the entire midnight meridian. We found that, because tail stretching increases field line curvature near the midplane but decreases curvature elsewhere, accessibility to the ionosphere is increased by tail stretching in regions above and below the midplane, although accessibility of particles passing through the midplane is reduced. This result implies that satellites armed with electron beam accelerators may be able to visibly affect the atmosphere from distances greater than previously anticipated.

  12. Talk Show Science.

    Science.gov (United States)

    Moore, Mitzi Ruth

    1992-01-01

    Proposes having students perform skits in which they play the roles of the science concepts they are trying to understand. Provides the dialog for a skit in which hot and cold gas molecules are interviewed on a talk show to study how these properties affect wind, rain, and other weather phenomena. (MDH)

  13. Cyclic Stretch Alters Vascular Reactivity of Mouse Aortic Segments

    Directory of Open Access Journals (Sweden)

    Arthur Leloup

    2017-10-01

    Full Text Available Large, elastic arteries buffer the pressure wave originating in the left ventricle and are constantly exposed to higher amplitudes of cyclic stretch (10% than muscular arteries (2%. As a crucial factor for endothelial and smooth muscle cell function, cyclic stretch has, however, never been studied in ex vivo aortic segments of mice. To investigate the effects of cyclic stretch on vaso-reactivity of mouse aortic segments, we used the Rodent Oscillatory Tension Set-up to study Arterial Compliance (ROTSAC. The aortic segments were clamped at frequencies of 6–600 bpm between two variable preloads, thereby mimicking dilation as upon left ventricular systole and recoiling as during diastole. The preloads corresponding to different transmural pressures were chosen to correspond to a low, normal or high amplitude of cyclic stretch. At different time intervals, cyclic stretch was interrupted, the segments were afterloaded and isometric contractions by α1-adrenergic stimulation with 2 μM phenylephrine in the absence and presence of 300 μM L-NAME (eNOS inhibitor and/or 35 μM diltiazem (blocker of voltage-gated Ca2+ channels were measured. As compared with static or cyclic stretch at low amplitude (<10 mN or low frequency (0.1 Hz, cyclic stretch at physiological amplitude (>10 mN and frequency (1–10 Hz caused better ex vivo conservation of basal NO release with time after mounting. The relaxation of PE-precontracted segments by addition of ACh to stimulate NO release was unaffected by cyclic stretch. In the absence of basal NO release (hence, presence of L-NAME, physiological in comparison with aberrant cyclic stretch decreased the baseline tension, attenuated the phasic contraction by phenylephrine in the absence of extracellular Ca2+ and shifted the smaller tonic contraction more from a voltage-gated Ca2+ channel-mediated to a non-selective cation channel-mediated. Data highlight the need of sufficient mechanical activation of endothelial and

  14. Epithelial cell stretching and luminal acidification lead to a retarded development of stria vascularis and deafness in mice lacking pendrin.

    Directory of Open Access Journals (Sweden)

    Hyoung-Mi Kim

    2011-03-01

    Full Text Available Loss-of-function mutations of SLC26A4/pendrin are among the most prevalent causes of deafness. Deafness and vestibular dysfunction in the corresponding mouse model, Slc26a4(-/-, are associated with an enlargement and acidification of the membranous labyrinth. Here we relate the onset of expression of the HCO(3 (- transporter pendrin to the luminal pH and to enlargement-associated epithelial cell stretching. We determined expression with immunocytochemistry, cell stretching by digital morphometry and pH with double-barreled ion-selective electrodes. Pendrin was first expressed in the endolymphatic sac at embryonic day (E 11.5, in the cochlear hook-region at E13.5, in the utricle and saccule at E14.5, in ampullae at E16.5, and in the upper turn of the cochlea at E17.5. Epithelial cell stretching in Slc26a4(-/- mice began at E14.5. pH changes occurred first in the cochlea at E15.5 and in the endolymphatic sac at E17.5. At postnatal day 2, stria vascularis, outer sulcus and Reissner's membrane epithelial cells, and utricular and saccular transitional cells were stretched, whereas sensory cells in the cochlea, utricle and saccule did not differ between Slc26a4(+/- and Slc26a4(-/- mice. Structural development of stria vascularis, including vascularization, was retarded in Slc26a4(-/- mice. In conclusion, the data demonstrate that the enlargement and stretching of non-sensory epithelial cells precedes luminal acidification in the cochlea and the endolymphatic sac. Stretching and luminal acidification may alter cell-to-cell communication and lead to the observed retarded development of stria vascularis, which may be an important step on the path to deafness in Slc26a4(-/- mice, and possibly in humans, lacking functional pendrin expression.

  15. Extracting local stretching from left ventricle angiography data

    Science.gov (United States)

    Mishra, Sanjoy K.; Goldgof, Dmitry B.

    1991-07-01

    This paper presents a new method for extracting local surface stretching from the left ventricle (LV) cineangiography data. The algorithm is based on Gaussian curvature for surface stretching recovery under more realistic conformal motion assumption. During conformal motion surface stretching can vary over the surface patch. In particular, surface stretching can be approximated using linear or quadratic (or higher order) functions. Then, coefficients of the approximating function can be calculated and surface stretching computed from changes in surface curvature at corresponding points. For example, linear approximation requires three point correspondences (between consecutive time frames) within small surface patch. The authors demonstrate the higher precision of the new approach (as compared to homothetic assumption in the authors' earlier work) on simulated and real data of the left ventricle of the human heart. The data set was provided by Dr. Alistair Young of the University of Auckland, New Zealand, and consists of the tracked locations of eleven bifurcation points of the left coronary artery and the tracked locations of 292 vessel points for one cardiac cycle (60 frames/cycle).

  16. Controlled cyclic stretch bioreactor for tissue-engineered heart valves.

    Science.gov (United States)

    Syedain, Zeeshan H; Tranquillo, Robert T

    2009-09-01

    A tissue-engineered heart valve (TEHV) represents the ultimate valve replacement, especially for juvenile patients given its growth potential. To date, most TEHV bioreactors have been developed based on pulsed flow of culture medium through the valve lumen to induce strain in the leaflets. Using a strategy for controlled cyclic stretching of tubular constructs reported previously, we developed a controlled cyclic stretch bioreactor for TEHVs that leads to improved tensile and compositional properties. The TEHV is mounted inside a latex tube, which is then cyclically pressurized with culture medium. The root and leaflets stretch commensurately with the latex, the stretching being dictated by the stiffer latex and thus controllable. Medium is also perfused through the lumen at a slow rate in a flow loop to provide nutrient delivery. Fibrin-based TEHVs prepared with human dermal fibroblasts were subjected to three weeks of cyclic stretching with incrementally increasing strain amplitude. The TEHV possessed the tensile stiffness and stiffness anisotropy of leaflets from sheep pulmonary valves and could withstand cyclic pulmonary pressures with similar distension as for a sheep pulmonary artery.

  17. Influence of chronic stretching on muscle performance: Systematic review.

    Science.gov (United States)

    Medeiros, D M; Lima, C S

    2017-08-01

    The aim of the current study was to investigate the influence of chronic stretching on muscle performance (MP) by a systematic review. The search strategy included MEDLINE, PEDro, Cochrane CENTRAL, LILACS, and manual search from inception to June 2016. Randomized and controlled clinical trials, non-randomized, and single group studies that have analyzed the influence of flexibility training (FT) (using any stretching technique) on MP were included. Differently, studies with special populations (children, elderly, and people with any dysfunction/disease), and articles that have used FT protocols shorter than three weeks or 12 sessions were excluded. The MP assessment could have been performed by functional tests (e.g. jump, sprint, stretch-shortening cycle tasks), isometric contractions, and/or isotonic contractions. Twenty-eight studies were included out of 513. Seven studies evaluated MP by stretch-shortening cycle tasks, Ten studies evaluated MP by isometric contractions, and 13 studies assessed MP by isotonic contractions. We were unable to perform a meta-analysis due to the high heterogeneity among the included studies. In an individual study level analysis, we identified that 14 studies found positive effects of chronic stretching on MP. The improvements were observed only in functional tests and isotonic contractions, isometric contractions were not affected by FT. Therefore, FT might have an influence on dynamic MP. However, more studies are necessary to confirm whether FT can positively affect MP. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. The role of substrate pre-stretch in post-wrinkling bifurcations.

    Science.gov (United States)

    Auguste, Anesia; Jin, Lihua; Suo, Zhigang; Hayward, Ryan C

    2014-09-14

    When a stiff film on a soft substrate is compressed, the surface of the film forms wrinkles, with tunable wavelengths and amplitudes that enable a variety of applications. As the compressive strain increases, the film undergoes post-wrinkling bifurcations, leading to period doubling and eventually to formation of localized folds or ridges. Here we study the post-wrinkling bifurcations in films on pre-stretched substrates. Through a combination of experiments and simulations, we demonstrate that pre-stretched substrates not only show substantial shifts in the critical strain for the onset of post-wrinkling bifurcations, but also exhibit qualitatively different post-wrinkled states. In particular, we report on the stabilization of wrinkles in films on pre-tensioned substrates and the emergence of 'chaotic' morphologies in films on pre-compressed substrates.

  19. Physics Reality Show

    Science.gov (United States)

    Erukhimova, Tatiana

    The attention span of K-12 students is very short; they are used to digesting information in short snippets through social media and TV. To get the students interested in physics, we created the Physics Reality Show: a series of staged short videos with duration no longer than a few minutes. Each video explains and illustrates one physics concept or law through a fast-paced sequence of physics demonstrations and experiments. The cast consists entirely of physics undergraduate students with artistic abilities and substantial experience in showing physics demonstrations at current outreach events run by the department: Physics Shows and Physics & Engineering Festival. Undergraduate students are of almost the same age as their high-school audience. They are in the best position to connect with kids and convey their fascination with physics. The PI and other faculty members who are involved in the outreach advise and coach the cast. They help students in staging the episodes and choosing the most exciting and relevant demonstrations. Supported by the APS mini-outreach Grant.

  20. Acute Effects of Contract-Relax Stretching vs. TENS in Young Subjects With Anterior Knee Pain: A Randomized Controlled Trial.

    Science.gov (United States)

    Valenza, Marie C; Torres-Sánchez, Irene; Cabrera-Martos, Irene; Valenza-Demet, Gerald; Cano-Cappellacci, Marcelo

    2016-08-01

    Valenza, MC, Torres-Sánchez, I, Cabrera-Martos, I, Valenza-Demet, G, and Cano-Cappellacci, M. Acute effects of contract-relax stretching vs. TENS in young subjects with anterior knee pain: A randomized controlled trial. J Strength Cond Res 30(8): 2271-2278, 2016-The aim of this study was to examine the immediate effects on pressure point tenderness, range of motion (ROM), and vertical jump (VJ) of contract-relax stretching vs. transcutaneous electrical nerve stimulation (TENS) therapy in individuals with anterior knee pain (AKP). Eighty-four subjects with AKP were randomly assigned to 1 of 3 different intervention groups: a contract-relax stretching group (n = 28), a TENS intervention group (n = 28), and a control group (n = 28). The participants included in the sample were both sex (37.5% men vs. 62.5% women) at a mean age of 21 years, with mean values of height and weight of 169 cm and 64 kg, respectively. The main outcome measures were knee ROM, pressure pain threshold (PPT), and VJ. The participants were assessed at baseline and immediately after treatment. In the case of VJ, at baseline, immediately after the intervention, at 3 and at 6 minutes posttreatment. The data analysis showed that PPT scores of participants in the stretching and TENS group significantly increased from pretest to posttest (p ≤ 0.05). A significant increase pre- to posttreatment in ROM (p < 0.001) was also observed in both treatment groups. In VJ measures, TENS and stretching groups showed significant differences between preintervention and all postintervention values (p ≤ 0.05), whereas no significant differences were found in the control group. In conclusion, the results show significant pre-to-post-treatment effects in PPT, ROM, and VJ from both contract-relax stretching and TENS in young subjects with AKP.

  1. Investigating the role of musical genre in human perception of music stretching resistance

    OpenAIRE

    Chen, Jun; Wang, Chaokun

    2017-01-01

    To stretch a music piece to a given length is a common demand in people's daily lives, e.g., in audio-video synchronization and animation production. However, it is not always guaranteed that the stretched music piece is acceptable for general audience since music stretching suffers from people's perceptual artefacts. Over-stretching a music piece will make it uncomfortable for human psychoacoustic hearing. The research on music stretching resistance attempts to estimate the maximum stretchab...

  2. Wiener Index, Diameter, and Stretch Factor of a Weighted Planar Graph in Subquadratic Time

    DEFF Research Database (Denmark)

    Wulff-Nilsen, Christian

    We solve three open problems: the existence of subquadratic time algorithms for computing the Wiener index (sum of APSP distances) and the diameter (maximum distance between any vertex pair) of a planar graph with non-negative edge weights and the stretch factor of a plane geometric graph (maximu......*(log log n)^4/log n) expected time, where n is the number of vertices. We also show how to compute the Wiener index and diameter of an unweighted n-vertex subgraph-closed n^{0.5}-separable graph in O(n^2*log log n/log n) worst-case time and with O(n) space.......We solve three open problems: the existence of subquadratic time algorithms for computing the Wiener index (sum of APSP distances) and the diameter (maximum distance between any vertex pair) of a planar graph with non-negative edge weights and the stretch factor of a plane geometric graph (maximum...... over all pairs of distinct vertices of the ratio between the graph distance and the Euclidean distance between the two vertices). More specifically, we show that the Wiener index and diameter can be found in O(n^2*(log log n)^4/log n) worst-case time and that the stretch factor can be found in O(n^2...

  3. A primary study on meridian-stretching of injected FDG using PET MPItool

    International Nuclear Information System (INIS)

    He Yijie; Tian Jiahe; Chen Yingmao; Yin Dayi; Zhang Jinming; Zhang Shuwen; Shao Mingzhe; Yao Shulin; Ding Weimin; Liu Zilai

    2002-01-01

    Objective: To show the images of tracer-stretching along the acupuncture meridian by use of PET with multipurpose imaging tool (MPItool's) fusion function. Methods: On 5 healthy volunteers, the authors measured the classical acupuncture points accurately with the biophysical measuring method. 18 F-fluorodeoxyglucose (FDG) was injected into the selected points, the others points along the same meridian were labelled with 18 F-FDG applied on the correspondent skin area of 2 . With the same body position, the transmission image and emission image was acquired respectively and fused with MPItool and its 3D display system. Results: The authors clearly showed not only the meridian-stretching images of the tracer, but also figured out the depth of the study points. The depth at SHANGJUXU point was about 3.8 cm and at ZUSANLI point was about 5,0 cm. The depths basically fit the classically documented ones of the correspondent acupuncture points. Conclusions: Using PET MPItool the authors preliminarily demonstrated that the tracer injected at the acupuncture point stretches along the correspondent meridian, and the depths of the meridian and the points (SHANGJUXU, ZUSANLI) detected are almost accordant with the classically documented ones

  4. Mechanical stretching of proteins-a theoretical survey of the Protein Data Bank

    International Nuclear Information System (INIS)

    Sulkowska, Joanna I; Cieplak, Marek

    2007-01-01

    The mechanical stretching of single proteins has been studied experimentally for about 50 proteins, yielding a variety of force patterns and peak forces. Here we perform a theoretical survey of proteins of known native structure and map out the landscape of possible dynamical behaviours under stretching at constant speed. We consider 7510 proteins comprising not more than 150 amino acids and 239 longer proteins. The model used is constructed based on the native geometry. It is solved by methods of molecular dynamics and validated by comparing the theoretical predictions to experimental results. We characterize the distribution of peak forces and investigate correlations with the system size and with the structure classification as characterized by the CATH scheme. Despite the presence of such correlations, proteins with the same CATH index may belong to different classes of dynamical behaviour. We identify proteins with the biggest forces and show that they belong to few topology classes. We determine which protein segments act as mechanical clamps and show that, in most cases, they correspond to long stretches of parallel β-strands, but other mechanisms are also possible. (topical review)

  5. Localization and stretch-dependence of lung elastase activity in development and compensatory growth.

    Science.gov (United States)

    Young, Sarah Marie; Liu, Sheng; Joshi, Rashika; Batie, Matthew R; Kofron, Matthew; Guo, Jinbang; Woods, Jason C; Varisco, Brian Michael

    2015-04-01

    Synthesis and remodeling of the lung matrix is necessary for primary and compensatory lung growth. Because cyclic negative force is applied to developing lung tissue during the respiratory cycle, we hypothesized that stretch is a critical regulator of lung matrix remodeling. By using quantitative image analysis of whole-lung and whole-lobe elastin in situ zymography images, we demonstrated that elastase activity increased twofold during the alveolar stage of postnatal lung morphogenesis in the mouse. Remodeling was restricted to alveolar walls and ducts and was nearly absent in dense elastin band structures. In the mouse pneumonectomy model of compensatory lung growth, elastase activity increased threefold, peaking at 14 days postpneumonectomy and was higher in the accessory lobe compared with other lobes. Remodeling during normal development and during compensatory lung growth was different with increased major airway and pulmonary arterial remodeling during development but not regeneration, and with homogenous remodeling throughout the parenchyma during development, but increased remodeling only in subpleural regions during compensatory lung growth. Left lung wax plombage prevented increased lung elastin during compensatory lung growth. To test whether the adult lung retains an innate capacity to remodel elastin, we developed a confocal microscope-compatible stretching device. In ex vivo adult mouse lung sections, lung elastase activity increased exponentially with strain and in peripheral regions of lung more than in central regions. Our study demonstrates that lung elastase activity is stretch-dependent and supports a model in which externally applied forces influence the composition, structure, and function of the matrix during periods of alveolar septation. Copyright © 2015 the American Physiological Society.

  6. Mechanical stretch increases CCN2/CTGF expression in anterior cruciate ligament-derived cells

    International Nuclear Information System (INIS)

    Miyake, Yoshiaki; Furumatsu, Takayuki; Kubota, Satoshi; Kawata, Kazumi; Ozaki, Toshifumi; Takigawa, Masaharu

    2011-01-01

    Highlights: → CCN2/CTGF localizes to the ligament-to-bone interface, but is not to the midsubstance region of human anterior cruciate ligament (ACL). → Mechanical stretch induces higher increase of CCN2/CTGF gene expression and protein secretion in ACL interface cells compared with ACL midsubstance cells. → CCN2/CTGF treatment stimulates the proliferation of ACL interface cells. -- Abstract: Anterior cruciate ligament (ACL)-to-bone interface serves to minimize the stress concentrations that would arise between two different tissues. Mechanical stretch plays an important role in maintaining cell-specific features by inducing CCN family 2/connective tissue growth factor (CCN2/CTGF). We previously reported that cyclic tensile strain (CTS) stimulates α1(I) collagen (COL1A1) expression in human ACL-derived cells. However, the biological function and stress-related response of CCN2/CTGF were still unclear in ACL fibroblasts. In the present study, CCN2/CTGF was observed in ACL-to-bone interface, but was not in the midsubstance region by immunohistochemical analyses. CTS treatments induced higher increase of CCN2/CTGF expression and secretion in interface cells compared with midsubstance cells. COL1A1 expression was not influenced by CCN2/CTGF treatment in interface cells despite CCN2/CTGF stimulated COL1A1 expression in midsubstance cells. However, CCN2/CTGF stimulated the proliferation of interface cells. Our results suggest that distinct biological function of stretch-induced CCN2/CTGF might regulate region-specific phenotypes of ACL-derived cells.

  7. Dynamics of the OH stretching mode in crystalline Ba(ClO4)2.3H2O

    Science.gov (United States)

    Hutzler, Daniel; Brunner, Christian; Petkov, Petko St.; Heine, Thomas; Fischer, Sighart F.; Riedle, Eberhard; Kienberger, Reinhard; Iglev, Hristo

    2018-02-01

    The vibrational dynamics of the OH stretching mode in Ba(ClO4)2 trihydrate are investigated by means of femtosecond infrared spectroscopy. The sample offers plane cyclic water trimers in the solid phase that feature virtually no hydrogen bond interaction between the water molecules. Selective excitation of the symmetric and asymmetric stretching leads to fast population redistribution, while simultaneous excitation yields quantum beats, which are monitored via a combination tone that dominates the overtone spectrum. The combination of steady-state and time-resolved spectroscopy with quantum chemical simulations and general theoretical considerations gives indication of various aspects of symmetry breakage. The system shows a joint population lifetime of 8 ps and a long-lived coherence between symmetric and asymmetric stretching, which decays with a time constant of 0.6 ps.

  8. Mixed convection flow of couple stress nanofluid over oscillatory stretching sheet with heat absorption/generation effects

    Science.gov (United States)

    Khan, Sami Ullah; Shehzad, Sabir Ali; Rauf, Amar; Ali, Nasir

    2018-03-01

    The aim of this article is to highlight the unsteady mixed convective couple stress nanoliquid flow passed through stretching surface. The flow is generated due to periodic oscillations of sheet. An appropriate set of dimensionless variables are used to reduce the independent variables in governing equations arising from mathematical modeling. An analytical solution has been computed by employing the technique of homotopy method. The outcomes of various sundry parameters like couple stress parameter, the ratio of angular velocity to stretching rate, thermophoresis parameter, Hartmann number, Prandtl number, heat source/sink parameter, Schmidt number described graphically and in tabular form. It is observed that the velocity profile increases by increasing mixed convection parameter and concentration buoyancy parameter. The temperature enhances for larger values of Hartmann number and Brownian. The concentration profile increases by increasing thermophoresis parameter. Results show that wall shear stress increases by increasing couple stress parameter and ratio of oscillating frequency to stretching rate.

  9. Dynamic Contractility and Efficiency Impairments in Stretch-Shortening Cycle Are Stretch-Load-Dependent After Training-Induced Muscle Damage

    NARCIS (Netherlands)

    Vaczi, Mark; Racz, Levente; Hortobagyi, Tibor; Tihanyi, Jozsef

    Vaczi, M, Racz, L, Hortobagyi, T, and Tihanyi, J. Dynamic contractility and efficiency impairments in stretch-shortening cycle are stretch-load-dependent after training-induced muscle damage. J Strength Cond Res 27(8): 2171-2179, 2013To determine the acute task and stretch-load dependency of

  10. Tail modeling in a stretched magnetosphere. I - Methods and transformations

    Science.gov (United States)

    Stern, David P.

    1987-01-01

    A new method is developed for representing the magnetospheric field B as a distorted dipole field. Because Delta-B = 0 must be maintained, such a distortion may be viewed as a transformation of the vector potential A. The simplest form is a one-dimensional 'stretch transformation' along the x axis, concisely represented by the 'stretch function' f(x), which is also a convenient tool for representing features of the substorm cycle. One-dimensional stretch transformations are extended to spherical, cylindrical, and parabolic coordinates and then to arbitrary coordinates. It is shown that distortion transformations can be viewed as mappings of field lines from one pattern to another; the final result only requires knowledge of the field and not of the potentials. General transformations in Cartesian and arbitrary coordinates are derived, and applications to field modeling, field line motion, MHD modeling, and incompressible fluid dynamics are considered.

  11. Alignment of Disks with Lagrangian Stretching in Turbulence

    Science.gov (United States)

    Hunt, Conor; Tierney, Lydia; Kramel, Stefan; Voth, Greg

    2015-11-01

    We study Lagrangian stretching in isotropic turbulence in order to understand both the rotations of disks and the preferential alignment of vorticity with the intermediate strain rate eigenvector. Using velocity gradient tensors from a numerical simulation of homogeneous isotropic turbulence at Rλ = 180, we calculate the Cauchy-Green strain tensors whose eigenvectors provide a natural basis for studying stretching phenomenon. Previous work has shown that rods preferentially align with the vorticity as a result of both quantities independently aligning with the extensional Cauchy-Green eigenvector. In contrast, disks orient with their symmetry axis perpendicular to vorticity and preferentially align with the compressional Cauchy-Green eigenvector. We also find that the intermediate strain rate eigenvector is aligned with the extensional Cauchy-Green eigenvector. A natural consequence is that the intermediate strain rate eigenvector is aligned with the vorticity vector since conservation of angular momentum aligns vorticity with the direction it has been stretched.

  12. Stretching of red blood cells at high strain rates

    Science.gov (United States)

    Mancuso, J. E.; Ristenpart, W. D.

    2017-10-01

    Most work on the mechanical behavior of red blood cells (RBCs) in flow has focused on simple shear flows. Relatively little work has examined RBC deformations in the physiologically important extensional flow that occurs at the entrance to a constriction. In particular, previous work suggests that RBCs rapidly stretch out and then retract upon entering the constriction, but to date no model predicts this behavior for the extremely high strain rates typically experienced there. In this Rapid Communication, we use high speed video to perform systematic measurements of the dynamic stretching behavior of RBCs as they enter a microfluidic constriction. We demonstrate that both the Kelvin-Voigt and Skalak viscoelastic models capture the observed stretching dynamics, up to strain rates as high as 2000 s-1. The results indicate that the effective elastic modulus of the RBC membrane at these strain rates is an order of magnitude larger than moduli measured by micropipette aspiration or other low strain rate techniques.

  13. Effects of static stretching on 1-mile uphill run performance.

    Science.gov (United States)

    Lowery, Ryan P; Joy, Jordan M; Brown, Lee E; Oliveira de Souza, Eduardo; Wistocki, David R; Davis, Gregory S; Naimo, Marshall A; Zito, Gina A; Wilson, Jacob M

    2014-01-01

    It is previously demonstrated that static stretching was associated with a decrease in running economy and distance run during a 30-minute time trial in trained runners. Recently, the detrimental effects of static stretching on economy were found to be limited to the first few minutes of an endurance bout. However, economy remains to be studied for its direct effects on performance during shorter endurance events. The aim of this study was to investigate the effects of static stretching on 1-mile uphill run performance, electromyography (EMG), ground contact time (GCT), and flexibility. Ten trained male distance runners aged 24 ± 5 years with an average VO2max of 64.9 ± 6.5 mL·kg-1·min-1 were recruited. Subjects reported to the laboratory on 3 separate days interspersed by 72 hours. On day 1, anthropometrics and V[Combining Dot Above]O2max were determined on a motor-driven treadmill. On days 2 and 3, subjects performed a 5-minute treadmill warm-up and either performed a series of 6 lower-body stretches for three 30-second repetitions or sat still for 10 minutes. Time to complete a 1-mile run under stretching and nonstretching conditions took place in randomized order. For the performance run, subjects were instructed to run as fast as possible at a set incline of 5% until a distance of 1 mile was completed. Flexibility from the sit and reach test, EMG, GCT, and performance, determined by time to complete the 1-mile run, were recorded after each condition. Time to complete the run was significantly less (6:51 ± 0:28 minutes) in the nonstretching condition as compared with the stretching condition (7:04 ± 0:32 minutes). A significant condition-by-time interaction for muscle activation existed, with no change in the nonstretching condition (pre 91.3 ± 11.6 mV to post 92.2 ± 12.9 mV) but increased in the stretching condition (pre 91.0 ± 11.6 mV to post 105.3 ± 12.9 mV). A significant condition-by-time interaction for GCT was also present, with no changes in

  14. Directional Cell Migration in Response to Repeated Substratum Stretching

    Science.gov (United States)

    Okimura, Chika; Iwadate, Yoshiaki

    2017-10-01

    Crawling migration plays an essential role in a variety of biological phenomena, including development, wound healing, and immune system function. Migration properties such as anterior-posterior polarity, directionality, and velocity are regulated not only by the reception of a chemoattractant but also by sensing mechanical inputs from the external environment. In this review, we describe the mechanical response of migrating cells, particularly under repeated stretching of the elastic substratum, highlighting the fact that there appear to be two independent mechanosensing systems that generate the polarity needed for migration. Cells that have no stress fibers, such as Dictyostelium cells and neutrophil-like differentiated HL-60 cells, migrate perpendicular to the stretching direction via myosin II localization. Cells that do possess stress fibers, however, such as fish keratocytes, migrate parallel to the stretching via a stress-fiber-dependent process.

  15. Not a "reality" show.

    Science.gov (United States)

    Wrong, Terence; Baumgart, Erica

    2013-01-01

    The authors of the preceding articles raise legitimate questions about patient and staff rights and the unintended consequences of allowing ABC News to film inside teaching hospitals. We explain why we regard their fears as baseless and not supported by what we heard from individuals portrayed in the filming, our decade-long experience making medical documentaries, and the full un-aired context of the scenes shown in the broadcast. The authors don't and can't know what conversations we had, what documents we reviewed, and what protections we put in place in each televised scene. Finally, we hope to correct several misleading examples cited by the authors as well as their offhand mischaracterization of our program as a "reality" show.

  16. Short Term Effects of Neurodynamic Stretching and Static Stretching Techniques on Hamstring Muscle Flexibility in Healthy Male Subjects

    Directory of Open Access Journals (Sweden)

    Adel Rashad Ahmed

    2016-05-01

    Full Text Available Flexibility is a key component of rehabilitation and inadequate muscle extensibility remains a commonly accepted factor for musculoskeletal disorders. Studies on the most optimal technique for improving muscle flexibility are a widely debated. The aim of the study was to compare the effectiveness of neurodynamic and static stretching techniques on hamstring flexibility in healthy male subjects. This study was a randomized experimental trial; forty healthy male subjects with hamstring tightness were randomly divided into two equal groups: The neurodynamic group and the static stretching group. Treatment was given for 5 consecutive days and the outcomes were measured using Active knee Extension Test and Straight Leg Raising. There was a significant improvement in hamstring flexibility following application of both neurodynamic and static stretching but the improvement in the neurodynamic group (p<0.001 was better than that of the static group (p<0.02. Results suggest that a neurodynamic stretching could increase hamstring flexibility to a greater extent than static stretching in healthy male subjects with a tight hamstring.

  17. Cyclic Mechanical Stretch Up-regulates Hepatoma-Derived Growth Factor Expression in Cultured Rat Aortic Smooth Muscle Cells.

    Science.gov (United States)

    Kao, Ying-Hsien; Chen, Po-Han; Sun, Cheuk-Kwan; Chang, Yo-Chen; Lin, Yu-Chun; Tsai, Ming-Shian; Lee, Po-Huang; Cheng, Cheng-I

    2018-02-21

    Hepatoma-derived growth factor (HDGF) is a potent mitogen for vascular smooth muscle cells (SMCs) during embryogenesis and injury repair of vessel walls. Whether mechanical stimuli modulate HDGF expression remains unknown. This study aimed at investigating whether cyclic mechanical stretch plays a regulatory role in HDGF expression and regenerative cytokine production in aortic SMCs. A SMC cell line was grown on a silicone-based elastomer chamber with extracellular matrix coatings (either type I collagen or fibronectin) and received cyclic and uni-axial mechanical stretches with 10% deformation at frequency 1 Hz. Morphological observation showed that fibronectin coating provided better cell adhesion and spreading and that consecutive 6 hours of cyclic mechanical stretch remarkably induced reorientation and realignment of SMCs. Western blotting detection demonstrated that continuous mechanical stimuli elicited up-regulation of HDGF and PCNA, a cell proliferative marker. Signal kinetic profiling study indicated that cyclic mechanical stretch induced signaling activity in RhoA/ROCK and PI3K/Akt cascades. Kinase inhibition study further showed that blockade of PI3K activity suppressed the stretch-induced TNF-a, whereas RhoA/ROCK inhibition significantly blunted the IL-6 production and HDGF over-expression. Moreover, siRNA-mediated HDGF gene silencing significantly suppressed constitutive expression of IL-6, but not TNF-α, in SMCs. These findings support the role of HDGF in maintaining vascular expression of IL-6, which has been regarded a crucial regenerative factor for acute vascular injury. In conclusion, cyclic mechanical stretch may maintain constitutive expression of HDGF in vascular walls and be regarded an important biophysical regulator in vascular regeneration. ©2018 The Author(s).

  18. Showing Value (Editorial

    Directory of Open Access Journals (Sweden)

    Denise Koufogiannakis

    2009-06-01

    Full Text Available When Su Cleyle and I first decided to start Evidence Based Library and Information Practice, one of the things we agreed upon immediately was that the journal be open access. We knew that a major obstacle to librarians using the research literature was that they did not have access to the research literature. Although Su and I are both academic librarians who can access a wide variety of library and information literature from our institutions, we belong to a profession where not everyone has equal access to the research in our field. Without such access to our own body of literature, how can we ever hope for practitioners to use research evidence in their decision making? It would have been contradictory to the principles of evidence based library and information practice to do otherwise.One of the specific groups we thought could use such an open access venue for discovering research literature was school librarians. School librarians are often isolated and lacking access to the research literature that may help them prove to stakeholders the importance of their libraries and their role within schools. Certainly, school libraries have been in decline and the use of evidence to show value is needed. As Ken Haycock noted in his 2003 report, The Crisis in Canada’s School Libraries: The Case for Reform and Reinvestment, “Across the country, teacher-librarians are losing their jobs or being reassigned. Collections are becoming depleted owing to budget cuts. Some principals believe that in the age of the Internet and the classroom workstation, the school library is an artifact” (9. Within this context, school librarians are looking to our research literature for evidence of the impact that school library programs have on learning outcomes and student success. They are integrating that evidence into their practice, and reflecting upon what can be improved locally. They are focusing on students and showing the impact of school libraries and

  19. Cell volume and membrane stretch independently control K+ channel activity

    DEFF Research Database (Denmark)

    Bomholtz, Sofia Hammami; Willumsen, Niels J; Olsen, Hervør L

    2009-01-01

    A number of potassium channels including members of the KCNQ family and the Ca(2+) activated IK and SK, but not BK, are strongly and reversibly regulated by small changes in cell volume. It has been argued that this general regulation is mediated through sensitivity to changes in membrane stretch....... To test this hypothesis we have studied the regulation of KCNQ1 and BK channels after expression in Xenopus oocytes. Results from cell-attached patch clamp studies (approximately 50 microm(2) macropatches) in oocytes expressing BK channels demonstrate that the macroscopic volume-insensitive BK current...... that stretch and volume sensitivity can be considered two independent regulatory mechanisms....

  20. Management of stretch marks (with a focus on striae rubrae

    Directory of Open Access Journals (Sweden)

    Uwe Wollina

    2017-01-01

    Full Text Available Stretch marks are one of the most common benign cutaneous lesions and encountered esthetic problems. Striae rubrae and striae albae can be differentiated on the basis of clinical appearance. Histologically, disturbances of the dermal fiber network and local expression of receptors for sexual steroids have been detected. The epidermal changes are secondary. Prevention of stretch marks using topical ointments and oils is debatable. Treatment of striae rubrae by lasers and light devices improves appearance. Microneedling and non-ablative and fractionated lasers have been used. This review provides an overview on current treatment options with a special focus on laser treatments.

  1. Magnetohydrodynamic dissipative flow across the slendering stretching sheet with temperature dependent variable viscosity

    Directory of Open Access Journals (Sweden)

    M. Jayachandra Babu

    Full Text Available The boundary layer flow across a slendering stretching sheet has gotten awesome consideration due to its inexhaustible pragmatic applications in nuclear reactor technology, acoustical components, chemical and manufacturing procedures, for example, polymer extrusion, and machine design. By keeping this in view, we analyzed the two-dimensional MHD flow across a slendering stretching sheet within the sight of variable viscosity and viscous dissipation. The sheet is thought to be convectively warmed. Convective boundary conditions through heat and mass are employed. Similarity transformations used to change over the administering nonlinear partial differential equations as a group of nonlinear ordinary differential equations. Runge-Kutta based shooting technique is utilized to solve the converted equations. Numerical estimations of the physical parameters involved in the problem are calculated for the friction factor, local Nusselt and Sherwood numbers. Viscosity variation parameter and chemical reaction parameter shows the opposite impact to each other on the concentration profile. Heat and mass transfer Biot numbers are helpful to enhance the temperature and concentration respectively. Keywords: MHD, Variable viscosity, Viscous dissipation, Convective boundary conditions, Slendering stretching sheet

  2. Stretched inverse opal colloid crystal substrates-induced orientation of fibroblast

    International Nuclear Information System (INIS)

    Wang, Y C; Tang, Z M; Feng, Z Q; Xie, Z Y; Gu, Z Z

    2010-01-01

    Recently, there has been increasing interest in studying the interaction between mammalian cells and nanometer-sized structures. However, the effect of nanostructures on cell behavior, such as cell morphology and alignment, is still largely unknown. Inverse opal colloid crystal substrates, which can be stretched to produce nano-scale pore structures of different degrees of orientation, serve as a convenient model system to study the effect of nanotopography on cell morphology and cell alignment. In this work, we fabricated inverse opal colloidal crystal films that were either unstretched or stretched to three, four or six times their original length, producing pore structures of increasing degree of orientation. Human dermal fibroblast-fetal (HDF-f) cells were seeded and cultured on these four types of substrates. The results from fluorescence microscopy and scanning electron microscopy indicated that cells showed the highest degree of alignment when cultured on inverse opal colloid crystal films that were stretched the most (six times original length). The results also demonstrated that the orientation of nanostructures could affect both the morphology and growth direction of fibroblasts. The ability to control the direction of cell growth through the engineering of nanostructures could have important applications in tissue engineering, especially for tissues with anisotropic structures, such as cardiac muscle, blood vessel, tendon and ligament.

  3. EFFICACY OF CYRIAX PHYSIOTHERAPY VERSUS ECCENTRIC STRENGTHENING AND STRETCHING EXERCISES IN CHRONIC LATERAL EPICONDYLITIS PATIENTS

    Directory of Open Access Journals (Sweden)

    Madhusmita Koch

    2015-10-01

    Full Text Available Background: Lateral Epicondylitis is the most common lesion of the elbow, affecting the tendinous origin of the wrist extensors. Although conservative treatment of this condition has been the subject of numerous studies, there is no agreement as to the most effective management strategy. Therefore, this study was designed to compare the efficacy of Cyriax physiotherapy Versus Eccentric Strengthening and Stretching exercises in reducing the pain and improving the grip strength and functional status of the affected extremity in chronic lateral epicondylitis. Method: An experimental study design, 60 subjects meeting the inclusion criteria were selected for the study and were randomly assigned into two groups: Group A (N=30 received Cyriax Physiotherapy and Group B(N=30 received Eccentric strengthening and static stretching of Extensor Carpi Radialis Brevis. Low Level Laser Therapy was a common treatment for both the groups. After 4 weeks of treatment, assessment was performed using Visual Analogue Scale (VAS, Hand Held Dynamometer (HHD and Patient Rated Tennis Elbow Evaluation Questionnaire (PRTEE at 0 week and at the end of 4 weeks. Results: Data analysis revealed that there is no statistically significant difference between the groups in VAS, HHD and PRTEE scores i.e. average improvement post treatment in both the groups are equal, but within group comparisons showed significant improvements in both the groups. Conclusion: The efficacy of Cyriax Physiotherapy is equal to Eccentric Strengthening and Stretching Exercises in chronic lateral epicondylitis.

  4. Deletion of the huntingtin polyglutamine stretch enhances neuronal autophagy and longevity in mice.

    Directory of Open Access Journals (Sweden)

    Shuqiu Zheng

    2010-02-01

    Full Text Available Expansion of a stretch of polyglutamine in huntingtin (htt, the protein product of the IT15 gene, causes Huntington's disease (HD. Previous investigations into the role of the polyglutamine stretch (polyQ in htt function have suggested that its length may modulate a normal htt function involved in regulating energy homeostasis. Here we show that expression of full-length htt lacking its polyglutamine stretch (DeltaQ-htt in a knockin mouse model for HD (Hdh(140Q/DeltaQ, reduces significantly neuropil mutant htt aggregates, ameliorates motor/behavioral deficits, and extends lifespan in comparison to the HD model mice (Hdh(140Q/+. The rescue of HD model phenotypes is accompanied by the normalization of lipofuscin levels in the brain and an increase in the steady-state levels of the mammalian autophagy marker microtubule-associate protein 1 light chain 3-II (LC3-II. We also find that DeltaQ-htt expression in vitro increases autophagosome synthesis and stimulates the Atg5-dependent clearance of truncated N-terminal htt aggregates. DeltaQ-htt's effect on autophagy most likely represents a gain-of-function, as overexpression of full-length wild-type htt in vitro does not increase autophagosome synthesis. Moreover, Hdh(DeltaQ/DeltaQ mice live significantly longer than wild-type mice, suggesting that autophagy upregulation may be beneficial both in diseases caused by toxic intracellular aggregate-prone proteins and also as a lifespan extender in normal mammals.

  5. METODE ACTIVE ISOLATED STRETCHING (AIS DAN METODE HOLD RELAX STRETCHING (HRS SAMA EFEKTIF DALAM MENINGKATKAN FLEKSIBILITAS OTOT HAMSTRING PADA MAHASISWA AKADEMI FISIOTERAPI WIDYA HUSADA SEMARANG YANG MENGALAMI HAMSTRING MUSCLE TIGHTNESS (HMTs

    Directory of Open Access Journals (Sweden)

    Akhmad alfajri

    2015-08-01

    Full Text Available Students with Hamstring Muscle Tightness (HMTs will be at risk of Anterior Crusiatum Ligament (ACL, Low Back Pain (LBP and also Plantar Faciitis. One of the efforts to reduce tightness and improve hamstring muscle flexibility is stretching. Active Isolated Stretching (AIS and Hold Relax Stretching (HRS are the methods of influential stretching to improve muscle flexibility. The goal of the research is to prove that AIS method is equally effective with the HRS method to improve hamstring muscle flexibility to the HMTs patients. The research method was true experimental with pre and post test group design. The research was conducted for 3 weeks and the samples are 23 students in range of 18-25 years old students of physical therapy in Physical Therapy Academy of Widya Husada Semarang which divided into 2 groups; AIS group (n= 12 and HRS group (n= 11. The research used Sit and Reach Test (SRT as the measurement instrument. The result of the research was the average result of AIS group used SRT before treatment was 1.75 cm, SB= 4.309 and after treatment was 10. 58 cm, SB = 8. 005 within p= 0.000 (p 0.05. Those explain that the improvement of hamstring muscle flexibility to the two groups does not show any significant difference. Conclusion from this study was active isolated stretching method and hold relax stretching method are equally effective to improving muscle flexibility of hamstring muscle tightness students of physical therapy in Physical Therapy Academy of Widya Husada Semarang.

  6. Effect of Preactivation on Torque Enhancement by the Stretch-Shortening Cycle in Knee Extensors.

    Directory of Open Access Journals (Sweden)

    Atsuki Fukutani

    Full Text Available The stretch-shortening cycle is one of the most interesting topics in the field of sport sciences, because the performance of human movement is enhanced by the stretch-shortening cycle (eccentric contraction. The purpose of the present study was to examine whether the influence of preactivation on the torque enhancement by stretch-shortening cycle in knee extensors. Twelve men participated in this study. The following three conditions were conducted for knee extensors: (1 concentric contraction without preactivation (CON, (2 concentric contraction with eccentric preactivation (ECC, and (3 concentric contraction with isometric preactivation (ISO. Muscle contractions were evoked by electrical stimulation to discard the influence of neural activity. The range of motion of the knee joint was set from 80 to 140 degrees (full extension = 180 degrees. Angular velocities of the concentric and eccentric contractions were set at 180 and 90 degrees/s, respectively. In the concentric contraction phase, joint torques were recorded at 85, 95, and 105 degrees, and they were compared among the three conditions. In the early phase (85 degrees of concentric contraction, the joint torque was larger in the ECC and ISO conditions than in the CON condition. However, these clear differences disappeared in the later phase (105 degrees of concentric contraction. The results showed that joint torque was clearly different among the three conditions in the early phase whereas this difference disappeared in the later phase. Thus, preactivation, which is prominent in the early phase of contractions, plays an important role in torque enhancement by the stretch-shortening cycle in knee extensors.

  7. Effects of muscle stretching exercises in the treatment of fibromyalgia: a systematic review.

    Science.gov (United States)

    Lorena, Suélem Barros de; Lima, Maria do Carmo Correia de; Ranzolin, Aline; Duarte, Ângela Luiza Branco Pinto

    2015-01-01

    This study has the objective to systematize scientific evidences about the use of muscle stretching exercises in the treatment of FM. It was performed from retrospective research without chronological and linguistic limits, at databases of MEDLINE, LILACS, SciELO and PEDro, as well as at PubMed search tool. Data collection was performed by two independent reviewers in October 2012, with the search strategy formulated by crossing descriptors and relevant terms to the topic in English, Portuguese and Spanish languages. Randomized clinical trials, only with patients with a clinical diagnosis of fibromyalgia and muscle stretching exercises as a therapeutic measure at least in one of the intervention groups were included. Included studies were assessed for methodological quality using PEDro scale and their references analyzed to highlight additional sources. The search amounted to an average of 6,794 items. Only five articles were selected, one being excluded because of its low methodological quality. Pain was assessed unanimously. The method and timing of interventions varied widely, there was poor mention of the parameters used in the stretches and absence of specific physical examinations. There was significant improvement in all studies regarding pain, besides as related to quality of life and physical condition. It is clear the importance of muscle stretching in the treatment of FM, however, there is a need for further studies to establish the real benefits of the technique, because the majority of published studies shows low methodological quality and there is a lack of standardization regarding the use of this resource. Copyright © 2014 Elsevier Editora Ltda. All rights reserved.

  8. Imaging stretch-activated firing of spinal afferent nerve endings in mouse colon

    Directory of Open Access Journals (Sweden)

    Lee etravis

    2013-10-01

    Full Text Available Spinal afferent neurons play a major role in detecting noxious and innocuous stimuli from visceral organs, such as the gastrointestinal tract. However, all our understanding about spinal afferents has been obtained from recordings of spinal afferent axons, or cell bodies that lie outside the gut wall, or peripheral organ they innervate. No recordings have been made directly from spinal afferent nerve endings, which is where sensory transduction occurs. We developed a preparation whereby recordings could be made from rectal afferent nerve endings in the colon, to characterize mechanisms underlying sensory transduction. Dorsal root ganglia (L6-S2 were removed from mice, whilst retaining neural continuity with the colon. Fluo-4-AM was used to record from rectal afferent nerve endings in myenteric ganglia and circular muscle at 36oC. In slack (unstretched preparations of colon, no calcium transients were recorded from spinal afferent endings. However, in response to a maintained increase in circumferential diameter, a maintained discharge of calcium transients occurred simultaneously in multiple discrete varicosities along single axons of rectal afferents in myenteric ganglia and circular muscle. Stretch-activated calcium transients were resistant to hexamethonium and nifedipine, but were abolished by tetrodotoxin, CPA, BAPTA-AM, cobalt, gadolinium, or replacement of extracellular Na+ with NMDG. In summary, we present a novel preparation in which stretch-activated firing of spinal afferent nerve endings can be recorded, using calcium imaging. We show that circumferential stretch of the colon activates a maintained discharge of calcium transients simultaneously in varicosities along single rectal afferent endings in myenteric ganglia and circular muscle. Non-selective cation channels, TTX-sensitive Na+ channels and both extracellular calcium influx and intracellular Ca2+ stores are required for stretch-activated calcium transients in rectal afferent

  9. Acute effect of passive rest intervals and stretching exercise on multiple set performance

    Directory of Open Access Journals (Sweden)

    Antonio Claudio do Rosário Souza

    2009-01-01

    Full Text Available http://dx.doi.org/10.5007/1980-0037.2009v11n4p435 The objective of this study was to determine the acute effect of passive rest intervals and static stretching between resistance exercise sets on the number of maximal repetitions (RM, rating of perceived exertion (RPE, and cumulative number of repetitions in multiple sets with a workload adjusted by the 8RM test. Fourteen trained male subjects (24.4 ± 2.1 years; 79.1 ± 7.1 kg; 175.4 ± 5.6 cm were studied. On the first two visits, the subjects were submitted to the test and 8RM re-test using chest press (CP and squat (SQ exercises. On the two subsequent visits, all subjects were randomly assigned to two experimental situations: a 8RM test with a passive rest interval (PI; b 8RM test with static stretching (SS. The subjects performed three sets of CP and SQ, intercalated with 2 minutes of passive rest or 30 seconds of static stretching. ANOVA revealed a significant decrease (p < 0.05 in the second (PI = 6 ± 0.8 x SS = 5.2 ± 1.0 repetitions and third (PI = 4.1 ± 0.8 X SS = 3.3 ± 0.6 repetitions sets for CP and only in the third set (PI = 4.9 ± 0.8 X SS = 4.2 ± 1.0 repetitions for SQ. For RPE, the Wilcoxon test showed significant differences (p < 0.05 between all sets for CP and SQ. For the cumulative number of repetitions, the paired t-test revealed a significant decrease (p < 0.05 for CP (PI = 18.3 ± 1.5 X SS = 16.8 ± 1.6 repetitions. These results indicate that static stretching between resistance exercise sets decreases 8RM test performance.

  10. EFFECTIVENESS OF INSTUMENTAL ASSISTED SOFT TISSUE MOBILIZATION TECHNIQUE WITH STATIC STRETCHING IN SUBJECTS WITH PLANTAR FASCIITIS

    Directory of Open Access Journals (Sweden)

    Vinod Babu. K

    2014-08-01

    Full Text Available Background: Instrumental assisted soft tissue mobilization and static stretching found to be effective in plantar fasciitis, however the combined effectiveness of these techniques were unknown. The purpose of this study is to find the effect of Instrumental assisted soft tissue mobilization technique for plantar fascia combined with static stretching of triceps surae for subjects with chronic stage of Plantar Fasciitis on pain intensity, ankle dorsiflexion range of motion and functional disability. Methods: An experimental study design, selected subjects with chronic Plantar Fasciitis randomized subjects into each Study and Control group. Total of 40 subject’s data who completed study, 20 in each group, was used for analysis. Control group received conventional exercise while Study group received conventional exercises with Instrumental assisted soft tissue mobilization combined with static stretching of triceps surae muscle. Outcome measurements such as Intensity of pain using Numerical Pain Rating Scale-101 (NPRS-101, function disability using Foot Function Index Pain Subscale (FFI and ankle dorsiflexion active range of motion using Goniometer was measured before and after 2 weeks of intervention. Results: There is statistically significant improvement in means of NRS-101, ankle dorsiflexion active range of motion and Foot Function Index Pain Subscale after intervention in both groups. When the post-intervention means were compared between Study and Control group after 2 weeks of treatment there is statistically significant difference in means between the groups whereas study group showed greater percentage of improvement than control group. Conclusion: It is concluded that Instrumental assisted soft tissue mobilization technique combined with static stretching of triceps surae muscle is significantly effective than conventional exercises on reducing pain, improving ankle dorsiflexion range of motion and functional disability for subjects

  11. Reduced Mechanical Stretch Induces Enhanced Endothelin B Receptor-mediated Contractility via Activation of Focal Adhesion Kinase and Extra Cellular-regulated Kinase 1/2 in Cerebral Arteries from Rat

    DEFF Research Database (Denmark)

    Spray, Stine; Rasmussen, Marianne N P; Skovsted, Gry F

    2016-01-01

    ETB receptor agonist sarafotoxin 6c. The involvement of extracellular regulated kinase (ERK) 1/2 and focal adhesion kinase (FAK) were studied by their specific inhibitors U0126 and PF-228, respectively. Compared to their stretched counterparts, un-stretched MCA segments showed a significantly...

  12. Optimal design of tunable phononic bandgap plates under equibiaxial stretch

    International Nuclear Information System (INIS)

    Hedayatrasa, Saeid; Abhary, Kazem; Uddin, M S; Guest, James K

    2016-01-01

    Design and application of phononic crystal (PhCr) acoustic metamaterials has been a topic with tremendous growth of interest in the last decade due to their promising capabilities to manipulate acoustic and elastodynamic waves. Phononic controllability of waves through a particular PhCr is limited only to the spectrums located within its fixed bandgap frequency. Hence the ability to tune a PhCr is desired to add functionality over its variable bandgap frequency or for switchability. Deformation induced bandgap tunability of elastomeric PhCr solids and plates with prescribed topology have been studied by other researchers. Principally the internal stress state and distorted geometry of a deformed phononic crystal plate (PhP) changes its effective stiffness and leads to deformation induced tunability of resultant modal band structure. Thus the microstructural topology of a PhP can be altered so that specific tunability features are met through prescribed deformation. In the present study novel tunable PhPs of this kind with optimized bandgap efficiency-tunability of guided waves are computationally explored and evaluated. Low loss transmission of guided waves throughout thin walled structures makes them ideal for fabrication of low loss ultrasound devices and structural health monitoring purposes. Various tunability targets are defined to enhance or degrade complete bandgaps of plate waves through macroscopic tensile deformation. Elastomeric hyperelastic material is considered which enables recoverable micromechanical deformation under tuning finite stretch. Phononic tunability through stable deformation of phononic lattice is specifically required and so any topology showing buckling instability under assumed deformation is disregarded. Nondominated sorting genetic algorithm (GA) NSGA-II is adopted for evolutionary multiobjective topology optimization of hypothesized tunable PhP with square symmetric unit-cell and relevant topologies are analyzed through finite

  13. Immediate effects of different types of stretching exercises on badminton jump smash.

    Science.gov (United States)

    Jang, Hwi S; Kim, Daeho; Park, Jihong

    2017-04-13

    Since different types of stretching exercises may alter athletic performance, we compared the effects of three types of stretching exercises on badminton jump smash. Sixteen male collegiate badminton players performed one of three different stretching exercises in a counterbalanced order on different days. Static stretching had seven typical stretches, while dynamic stretching involved nine dynamic movements, and resistance dynamic stretching was performed with weighted vests and dumbbells. Before and after each stretching exercise, subjects performed 20 trials of jump smashes. Dependent measurements were the jump heights during jump smashes, velocities of jump-smashed shuttlecocks, and drop points of jump-smashed shuttlecocks. To test the effects of each stretching exercise, we performed mixed model ANOVAs and calculated between-time effect sizes (ES). Each stretching exercise improved the jump heights during jump smashes (type main effect: F2,75= 1.19, p=0.31; static stretching: 22.1%, pstretching: 30.1%, pstretching: 17.7%, p=0.03, ES: 0.98) and velocities of jump-smashed shuttlecocks (type main effect: F2,75= 2.18, p=0.12; static stretching: 5.7%, p=0.61, ES: 0.39; dynamic stretching: 3.4%, p=0.94, ES: 0.28; resistance dynamic stretching: 6%, p=0.50, ES: 0.66). However, there were no differences among the stretching exercises for any measurement. The drop point of jump-smashed shuttlecocks did not change (interaction: F2,75= 0.88, p=0.42). All stretching exercises improved badminton jump smash performance, but we could not determine the best protocol. Since badminton requires high-speed movement and explosive force, we suggest performing dynamic stretching or resistance dynamic stretching.

  14. The effect of middle and lower trapezius strength exercises and levator scapulae and upper trapezius stretching exercises in upper crossed syndrome.

    Science.gov (United States)

    Bae, Won-Sik; Lee, Hyun-Ok; Shin, Jae-Wook; Lee, Keon-Cheol

    2016-05-01

    [Purpose] The purpose of this study was to determine the effectiveness of strength and stretching exercises on upper crossed syndrome. [Subjects and Methods] After measuring cervical alignment using the Global Posture System, 30 students with forward head posture were selected and divided into two groups. The experimental group (n=15) participated in strength and stretching exercises, three times per week for 4 weeks. The control group (n=15) did not participate in the exercises. The exercise program comprised middle and lower trapezius strength exercises and levator scapulae and upper trapezius stretching exercises. The temperature of the posterior neck was then measured using digital infrared thermographic imaging. [Results] There was a significant difference between the pretest and posttest results in the experimental group, and a significant difference in posterior neck temperature between the two groups. [Conclusion] This study showed that middle and lower trapezius strength exercises and levator scapulae and upper trapezius stretching exercises are more effective for upper crossed syndrome.

  15. The effects of three types of piriform muscle stretching on muscle thickness and the medial rotation angle of the coxal articulation.

    Science.gov (United States)

    Park, Jun Chul; Shim, Jae Hun; Chung, Sin Ho

    2017-10-01

    [Purpose] The purpose of this study was three kinds of stretching methods and measured the change in the thickness of the piriform muscle in real time using ultrasound images and compared the medial rotation angle of the coxal articulation. [Subjects and Methods] Fourty-five subjects who attend B University in Cheonan, divided into three groups. The subjects in these three groups then underwent stretching with flexion of coxal articulation over 90°, stretching with flexion of coxal articulation under 90°, and muscle energy technique (MET) application. The main outcome measures were piriform muscle thickness and medial rotation angle of the coxal articulation. [Results] All groups showed decreased piriform muscle thickness and increased medial rotation angle of the coxal articulation. [Conclusion] Based on the above results, three kinds of piriform muscle stretching methods are effective of reduce muscle thickness and increase medial rotation angle of the coxal articulation.

  16. Stretching Local Dollars: A Small Town Guide to Matching Funds.

    Science.gov (United States)

    Brown, Hamilton

    The purpose of this guidebook is to help elected leaders of small towns and communities stretch their investments when matching funds are required to compete for a grant or to pay for development costs above the grant award itself. The federal "small cities" Community Development Block Grant (CDBG) is used as an example throughout the…

  17. Measurement of Reversed Extension Flow using the Filament Stretch Rheometer

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Skov, Anne Ladegaard; Nielsen, Jens Kromann

    2008-01-01

    ). The latter is applicable on highly extensible elastomers, whereas in LAOE measurements on liquids (including polymer melts) the LAOE flow needs to be imposed upon a constant strain rate uniaxial elongation. The used Filament Stretching Rheometer allows measurements on polymeric fluids (including polymeric...... melts) from room temperature until 200 degrees C....

  18. On zero variance Monte Carlo path-stretching schemes

    International Nuclear Information System (INIS)

    Lux, I.

    1983-01-01

    A zero variance path-stretching biasing scheme proposed for a special case by Dwivedi is derived in full generality. The procedure turns out to be the generalization of the exponential transform. It is shown that the biased game can be interpreted as an analog simulation procedure, thus saving some computational effort in comparison with the corresponding nonanalog game

  19. Mediators of Yoga and Stretching for Chronic Low Back Pain

    Directory of Open Access Journals (Sweden)

    Karen J. Sherman

    2013-01-01

    Full Text Available Although yoga is an effective treatment for chronic low back pain, little is known about the mechanisms responsible for its benefits. In a trial comparing yoga to intensive stretching and self-care, we explored whether physical (hours of back exercise/week, cognitive (fear avoidance, body awareness, and self-efficacy, affective (psychological distress, perceived stress, positive states of mind, and sleep, and physiological factors (cortisol, DHEA mediated the effects of yoga or stretching on back-related dysfunction (Roland-Morris Disability Scale (RDQ. For yoga, 36% of the effect on 12-week RDQ was mediated by increased self-efficacy, 18% by sleep disturbance, 9% by hours of back exercise, and 61% by the best combination of all possible mediators (6 mediators. For stretching, 23% of the effect was mediated by increased self-efficacy, 14% by days of back exercise, and 50% by the best combination of all possible mediators (7 mediators. In open-ended questions, ≥20% of participants noted the following treatment benefits: learning new exercises (both groups, relaxation, increased awareness, and the benefits of breathing (yoga, benefits of regular practice (stretching. Although both self-efficacy and hours of back exercise were the strongest mediators for each intervention, compared to self-care, qualitative data suggest that they may exert their benefits through partially distinct mechanisms.

  20. Entropy generation in MHD flow of a uniformly stretched vertical ...

    African Journals Online (AJOL)

    This paper reports the analytical calculation of the entropy generation due to heat and mass transfer and fluid friction in steady state of a uniformly stretched vertical permeable surface with heat and mass diffusive walls, by solving analytically the mass, momentum, species concentration and energy balance equation, using ...

  1. Anharmonic bend-stretch coupling in neat liquid water

    NARCIS (Netherlands)

    Lindner, Joerg; Cringus, Dan; Pshenichnikov, Maxim S.; Voehringer, Peter

    2007-01-01

    Femtosecond mid-IR spectroscopy is used to study the vibrational relaxation dynamics in neat liquid water. By exciting the bending vibration and probing the stretching mode, it is possible to reliably determine the bending and librational lifetimes of water. The anharmonic coupling between the

  2. Effect of Mechanical Stretching of the Skin on Collagen Fibril ...

    African Journals Online (AJOL)

    Stabilization of collagen fibres during development and through growth to maturation has now become fairly documented. In vitro effect of mechanical stretching of ratsf skin on oxidative deamination of ε-NH2-groups of lysine and hydroxylysine, and functional properties of its type . collagen were studied. Experiments were ...

  3. Effects of Warm-Up Stretching Exercises on Sprint Performance

    Science.gov (United States)

    Makaruk, Hubert; Makaruk, Beata; Kedra, Stanislaw

    2008-01-01

    Study aim: To assess direct effects of warm-up consisting of static and dynamic stretching exercises on sprint results attained by students differing in sprint performance. Material and methods: A group of 24 male and 19 female physical education students, including 12 and 9 sprinters, respectively. They performed warm-ups consisting of dynamic…

  4. A Japanese Stretching Intervention Can Modify Lumbar Lordosis Curvature

    NARCIS (Netherlands)

    Kadono, Norio; Tsuchiya, Kazushi; Uematsu, Azusa; Kamoshita, Hiroshi; Kiryu, Kazunori; Hortobagyi, Tibor; Suzuki, Shuji

    Study Design: Eighteen healthy male adults were assigned to either an intervention or control group. Objectives: Isogai dynamic therapy (IDT) is one of Japanese stretching interventions and has been practiced for over 70 years. However, its scientific quantitative evidence remains unestablished. The

  5. Flow of viscous fluid along an exponentially stretching curved surface

    Directory of Open Access Journals (Sweden)

    N.F. Okechi

    Full Text Available In this paper, we present the boundary layer analysis of flow induced by rapidly stretching curved surface with exponential velocity. The governing boundary value problem is reduced into self-similar form using a new similarity transformation. The resulting equations are solved numerically using shooting and Runge-Kutta methods. The numerical results depicts that the fluid velocity as well as the skin friction coefficient increases with the surface curvature, similar trend is also observed for the pressure. The dimensionless wall shear stress defined for this problem is greater than that of a linearly stretching curved surface, but becomes comparably less for a surface stretching with a power-law velocity. In addition, the result for the plane surface is a special case of this study when the radius of curvature of the surface is sufficiently large. The numerical investigations presented in terms of the graphs are interpreted with the help of underlying physics of the fluid flow and the consequences arising from the curved geometry. Keywords: Boundary layer flow, Curved surface, Exponential stretching, Curvature

  6. Vibrations of stretched damped beams under non-ideal boundary ...

    Indian Academy of Sciences (India)

    Stretched beam vibrations; non-ideal boundary conditions; method of multiple time scales. 1. Introduction. Beams are frequently used as design models for vibration analysis. In such analysis, types of support conditions are important and have direct effect on the solutions and natural fre- quencies. Different types of supports ...

  7. Stretch Intensity vs. Inflammation: A Dose-dependent Association?

    Directory of Open Access Journals (Sweden)

    Nikos Apostolopoulos BPHE

    2015-01-01

    Full Text Available The intensity of stretching is rarely reported in scientific literature. In this study, we examined the effects of stretching intensities at 30%, 60%, and 90% of maximum range of movement (mROM on the inflammatory response of the right hamstring muscle. Methods: A randomised within-subject trial was conducted with 11 healthy recreationally active males over a three week period. Participants were strapped into an isokinetic dynamometer in the supine position, with the right knee fastened in a knee immobilizer. After randomising the ROM percentages, the hamstring muscle was moved to one of the three chosen ROM percentages for that week and held there for 5 x 60 seconds followed by a 10 second rest between repetitions. A 5ml blood sample was collected pre-, immediately post, and at 24 hours post intervention for high sensitivity C-reactive protein (hsCRP assessments. Results: Significant increases in hsCRP levels were observed between 30% mROM and 90% mROM (p=0.004 and 60% mROM and 90% mROM (p=0.034, but not between 30% and 60% (p>0.05. Conclusions: Muscle stretching at submaximal levels does not elicit a significant systemic inflammatory responses. Keywords: Stretch intensity, inflammation, hsCRP

  8. MHD flow of a uniformly stretched vertical permeable membrane in ...

    African Journals Online (AJOL)

    Journal of the Nigerian Association of Mathematical Physics ... Abstract. We present a magneto - hydrodynamic flow of a uniformly stretched vertical permeable surface undergoing Arrhenius heat reaction. ... It is also established that maximum velocity occurs in the body of the fluid close to the surface and not the surface.

  9. Contact of a spherical probe with a stretched rubber substrate

    Science.gov (United States)

    Frétigny, Christian; Chateauminois, Antoine

    2017-07-01

    We report on a theoretical and experimental investigation of the normal contact of stretched neo-Hookean substrates with rigid spherical probes. Starting from a published formulation of surface Green's function for incremental displacements on a prestretched, neo-Hookean, substrate [J. Mech. Phys. Solids 56, 2957 (2008), 10.1016/j.jmps.2008.07.002], a model is derived for both adhesive and nonadhesive contacts. The shape of the elliptical contact area together with the contact load and the contact stiffness are predicted as a function of the in-plane stretch ratios λx and λy of the substrate. The validity of this model is assessed by contact experiments carried out using an uniaxally stretched silicone rubber. For stretch ratio below about 1.25, a good agreement is observed between theory and experiments. Above this threshold, some deviations from the theoretical predictions are induced as a result of the departure of the mechanical response of the silicone rubber from the neo-Hokeean description embedded in the model.

  10. Effect of Mechanical Stretching of the Skin on Collagen Fibril ...

    African Journals Online (AJOL)

    Dell

    It was recently established that, deformation of connective tissue cells under the influence of mechanical stretching intensifies the synthesis of structural biopolymers, particularly those of the collagen molecules, which are capable of associating into fibrils by self assembly (Buschmann et al., 1995,. Garbuzenko et al., 1997; ...

  11. Bruxism: Is There an Indication for Muscle-Stretching Exercises?

    NARCIS (Netherlands)

    Gouw, S.; Wijer, A. de; Creugers, N.H.J.; Kalaykova, S.I.

    2017-01-01

    Bruxism is a common phenomenon involving repetitive activation of the masticatory muscles. Muscle-stretching exercises are a recommended part of several international guidelines for musculoskeletal disorders and may be effective in management of the jaw muscle activity that gives rise to bruxism.

  12. Sport stretching : Effect on passive muscle stiffness of short hamstrings

    NARCIS (Netherlands)

    Halbertsma, JPK; vanBolhuis, AI; Goeken, LNH

    Objective: To evaluate the effects of one 10-minute stretch on muscle stiffness in subjects with short hamstrings. Design: Randomized control trial. Setting: Laboratory for human movement sciences in the department of rehabilitation of a university hospital. Subjects: Sixteen students from the

  13. The health of benthic diatom assemblages in lower stretch

    Indian Academy of Sciences (India)

    This study examines the ecological state of epilithic diatom assemblages along the lower stretch of Mandakini, a glacier-fed Himalayan river. The diatoms were sampled at four stations during winter and summer, only once in each season. Valve counts were obtained from Naphrax mounts prepared from each sample.

  14. A single molecule DNA flow stretching microscope for undergraduates

    NARCIS (Netherlands)

    Williams, Kelly; Grafe, Brendan; Burke, Kathryn M.; Tanner, Nathan; van Oijen, Antoine M.; Loparo, Joseph; Price, Allen C.

    2011-01-01

    The design of a simple, safe, and inexpensive single molecule flow stretching instrument is presented. The instrument uses a low cost upright microscope coupled to a webcam for imaging single DNA molecules that are tethered in an easy to construct microfluidic flow cell. The system requires no

  15. Acute effects of active isolated stretching on vertical jump ...

    African Journals Online (AJOL)

    The purpose of the study was to determine the acute effects of active isolated stretching on muscular peak power production. Sixty healthy, physically active volunteers (aged 18-28) participated as subjects in this study. Subjects were randomly assigned to two groups; the control group and the experimental group. Subjects ...

  16. Role Of Stretching Exercises In The Management Of Constipation In Spastic Cerebral Palsy.

    Science.gov (United States)

    Awan, Waqar Ahmed; Masood, Tahir

    2016-01-01

    Constipation is considered as one of the most common non-motor manifestations in cerebral palsy (CP). Along with other reasons, spasticity also contributes in developing constipation in CP, by decreasing mobility of trunk and lower extremities and abdominal viscera. Stretching exercises of upper extremities, trunk and lower extremities are routine management of spasticity in CP children. The objective of the study was to determine the role of stretching exercises in improving constipation symptoms in children with spastic cerebral palsy and to explore the association between spasticity and constipation among cerebral palsy children. Single-group Pretest-Posttest Design (Quasi Experimental Study Design). The study was conducted at Physiotherapy Department of National Institute of Rehabilitation Medicine (NIRM) Islamabad. Thirty spastic CP children - both male and female - with complaints of constipation were recruited through non-probability, convenience sampling. The mean age of the children was 7.55±1.33 years. Each child was assessed for defecation frequency (DF), constipation severity by constipation assessment scale (CAS) and level of spasticity by modified ash worth scale for spasticity (MASS) at baseline. Stretching exercises were performed for 30 seconds with five repetitions and at least once a day for six week, followed by positioning of patients in reflex inhibiting posture. Final data was collected using the same tools as done at the baseline. Paired samples t-test was used to analyse the rehabilitation-induced changes after 6 weeks. To determine association between spasticity and constipation Pearson product-moment correlation coefficient was used. The data was analysed through SPSS 20. Significant changes, compared to the baseline scores, were observed after 6 weeks of stretching exercises in MASS (2.53±0.62 Vs 1.53±0.77), DF (2.43±0.67 Vs 3.70±1.02) and CAS (7.23±1.50 Vs 5.43±1.73) with p≤0.05. The results also showed significant correlation

  17. Stretch force guides finger-like pattern of bone formation in suture.

    Science.gov (United States)

    Wu, Bo-Hai; Kou, Xiao-Xing; Zhang, Ci; Zhang, Yi-Mei; Cui, Zhen; Wang, Xue-Dong; Liu, Yan; Liu, Da-Wei; Zhou, Yan-Heng

    2017-01-01

    Mechanical tension is widely applied on the suture to modulate the growth of craniofacial bones. Deeply understanding the features of bone formation in expanding sutures could help us to improve the outcomes of clinical treatment and avoid some side effects. Although there are reports that have uncovered some biological characteristics, the regular pattern of sutural bone formation in response to expansion forces is still unknown. Our study was to investigate the shape, arrangement and orientation of new bone formation in expanding sutures and explore related clinical implications. The premaxillary sutures of rat, which histologically resembles the sutures of human beings, became wider progressively under stretch force. Micro-CT detected new bones at day 3. Morphologically, these bones were forming in a finger-like pattern, projecting from the maxillae into the expanded sutures. There were about 4 finger-like bones appearing on the selected micro-CT sections at day 3 and this number increased to about 18 at day 7. The average length of these projections increased from 0.14 mm at day 3 to 0.81 mm at day 7. The volume of these bony protuberances increased to the highest level of 0.12 mm3 at day 7. HE staining demonstrated that these finger-like bones had thick bases connecting with the maxillae and thin fronts stretching into the expanded suture. Nasal sections had a higher frequency of finger-like bones occuring than the oral sections at day 3 and day 5. Masson-stained sections showed stretched fibers embedding into maxillary margins. Osteocalcin-positive osteoblasts changed their shapes from cuboidal to spindle and covered the surfaces of finger-like bones continuously. Alizarin red S and calcein deposited in the inner and outer layers of finger-like bones respectively, which showed that longer and larger bones formed on the nasal side of expanded sutures compared with the oral side. Interestingly, these finger-like bones were almost paralleling with the direction

  18. Force encoding in muscle spindles during stretch of passive muscle.

    Science.gov (United States)

    Blum, Kyle P; Lamotte D'Incamps, Boris; Zytnicki, Daniel; Ting, Lena H

    2017-09-01

    Muscle spindle proprioceptive receptors play a primary role in encoding the effects of external mechanical perturbations to the body. During externally-imposed stretches of passive, i.e. electrically-quiescent, muscles, the instantaneous firing rates (IFRs) of muscle spindles are associated with characteristics of stretch such as length and velocity. However, even in passive muscle, there are history-dependent transients of muscle spindle firing that are not uniquely related to muscle length and velocity, nor reproduced by current muscle spindle models. These include acceleration-dependent initial bursts, increased dynamic response to stretch velocity if a muscle has been isometric, and rate relaxation, i.e., a decrease in tonic IFR when a muscle is held at a constant length after being stretched. We collected muscle spindle spike trains across a variety of muscle stretch kinematic conditions, including systematic changes in peak length, velocity, and acceleration. We demonstrate that muscle spindle primary afferents in passive muscle fire in direct relationship to muscle force-related variables, rather than length-related variables. Linear combinations of whole muscle-tendon force and the first time derivative of force (dF/dt) predict the entire time course of transient IFRs in muscle spindle Ia afferents during stretch (i.e., lengthening) of passive muscle, including the initial burst, the dynamic response to lengthening, and rate relaxation following lengthening. Similar to acceleration scaling found previously in postural responses to perturbations, initial burst amplitude scaled equally well to initial stretch acceleration or dF/dt, though later transients were only described by dF/dt. The transient increase in dF/dt at the onset of lengthening reflects muscle short-range stiffness due to cross-bridge dynamics. Our work demonstrates a critical role of muscle cross-bridge dynamics in history-dependent muscle spindle IFRs in passive muscle lengthening conditions

  19. Force encoding in muscle spindles during stretch of passive muscle.

    Directory of Open Access Journals (Sweden)

    Kyle P Blum

    2017-09-01

    Full Text Available Muscle spindle proprioceptive receptors play a primary role in encoding the effects of external mechanical perturbations to the body. During externally-imposed stretches of passive, i.e. electrically-quiescent, muscles, the instantaneous firing rates (IFRs of muscle spindles are associated with characteristics of stretch such as length and velocity. However, even in passive muscle, there are history-dependent transients of muscle spindle firing that are not uniquely related to muscle length and velocity, nor reproduced by current muscle spindle models. These include acceleration-dependent initial bursts, increased dynamic response to stretch velocity if a muscle has been isometric, and rate relaxation, i.e., a decrease in tonic IFR when a muscle is held at a constant length after being stretched. We collected muscle spindle spike trains across a variety of muscle stretch kinematic conditions, including systematic changes in peak length, velocity, and acceleration. We demonstrate that muscle spindle primary afferents in passive muscle fire in direct relationship to muscle force-related variables, rather than length-related variables. Linear combinations of whole muscle-tendon force and the first time derivative of force (dF/dt predict the entire time course of transient IFRs in muscle spindle Ia afferents during stretch (i.e., lengthening of passive muscle, including the initial burst, the dynamic response to lengthening, and rate relaxation following lengthening. Similar to acceleration scaling found previously in postural responses to perturbations, initial burst amplitude scaled equally well to initial stretch acceleration or dF/dt, though later transients were only described by dF/dt. The transient increase in dF/dt at the onset of lengthening reflects muscle short-range stiffness due to cross-bridge dynamics. Our work demonstrates a critical role of muscle cross-bridge dynamics in history-dependent muscle spindle IFRs in passive muscle

  20. GNG Motifs Can Replace a GGG Stretch during G-Quadruplex Formation in a Context Dependent Manner.

    Science.gov (United States)

    Das, Kohal; Srivastava, Mrinal; Raghavan, Sathees C

    2016-01-01

    G-quadruplexes are one of the most commonly studied non-B DNA structures. Generally, these structures are formed using a minimum of 4, three guanine tracts, with connecting loops ranging from one to seven. Recent studies have reported deviation from this general convention. One such deviation is the involvement of bulges in the guanine tracts. In this study, guanines along with bulges, also referred to as GNG motifs have been extensively studied using recently reported HOX11 breakpoint fragile region I as a model template. By strategic mutagenesis approach we show that the contribution from continuous G-tracts may be dispensible during G-quadruplex formation when such motifs are flanked by GNGs. Importantly, the positioning and number of GNG/GNGNG can also influence the formation of G-quadruplexes. Further, we assessed three genomic regions from HIF1 alpha, VEGF and SHOX gene for G-quadruplex formation using GNG motifs. We show that HIF1 alpha sequence harbouring GNG motifs can fold into intramolecular G-quadruplex. In contrast, GNG motifs in mutant VEGF sequence could not participate in structure formation, suggesting that the usage of GNG is context dependent. Importantly, we show that when two continuous stretches of guanines are flanked by two independent GNG motifs in a naturally occurring sequence (SHOX), it can fold into an intramolecular G-quadruplex. Finally, we show the specific binding of G-quadruplex binding protein, Nucleolin and G-quadruplex antibody, BG4 to SHOX G-quadruplex. Overall, our study provides novel insights into the role of GNG motifs in G-quadruplex structure formation which may have both physiological and pathological implications.

  1. GNG Motifs Can Replace a GGG Stretch during G-Quadruplex Formation in a Context Dependent Manner.

    Directory of Open Access Journals (Sweden)

    Kohal Das

    Full Text Available G-quadruplexes are one of the most commonly studied non-B DNA structures. Generally, these structures are formed using a minimum of 4, three guanine tracts, with connecting loops ranging from one to seven. Recent studies have reported deviation from this general convention. One such deviation is the involvement of bulges in the guanine tracts. In this study, guanines along with bulges, also referred to as GNG motifs have been extensively studied using recently reported HOX11 breakpoint fragile region I as a model template. By strategic mutagenesis approach we show that the contribution from continuous G-tracts may be dispensible during G-quadruplex formation when such motifs are flanked by GNGs. Importantly, the positioning and number of GNG/GNGNG can also influence the formation of G-quadruplexes. Further, we assessed three genomic regions from HIF1 alpha, VEGF and SHOX gene for G-quadruplex formation using GNG motifs. We show that HIF1 alpha sequence harbouring GNG motifs can fold into intramolecular G-quadruplex. In contrast, GNG motifs in mutant VEGF sequence could not participate in structure formation, suggesting that the usage of GNG is context dependent. Importantly, we show that when two continuous stretches of guanines are flanked by two independent GNG motifs in a naturally occurring sequence (SHOX, it can fold into an intramolecular G-quadruplex. Finally, we show the specific binding of G-quadruplex binding protein, Nucleolin and G-quadruplex antibody, BG4 to SHOX G-quadruplex. Overall, our study provides novel insights into the role of GNG motifs in G-quadruplex structure formation which may have both physiological and pathological implications.

  2. Expression and proliferation profiles of PKC, JNK and p38MAPK in physiologically stretched human bladder smooth muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Wazir, Romel; Luo, De-Yi; Dai, Yi; Yue, Xuan; Tian, Ye; Wang, Kun-Jie, E-mail: kunjiewangatscu@163.com

    2013-08-30

    Highlights: •Stretch induces proliferation in human bladder smooth muscle cells (HBSMC). •5% Equibiaxial elongation produces maximum proliferation. •Physiologic stretch decreases apoptotic cell death. •PKC is involved in functional modulation of bladder. •JNK and p38 are not involved in proliferating HBSMC. -- Abstract: Objective: To determine protein kinase C (PKC), c-Jun NH2-Terminal Kinase (JNK) and P38 mitogen-activated protein kinases (p38MAPK) expression levels and effects of their respective inhibitors on proliferation of human bladder smooth muscle cells (HBSMCs) when physiologically stretched in vitro. Materials and methods: HBSMCs were grown on silicone membrane and stretch was applied under varying conditions; (equibiaxial elongation: 2.5%, 5%, 10%, 15%, 20%, 25%), (frequency: 0.05, 0.1, 0.2, 0.5, 1 Hz). Optimal physiological stretch was established by assessing proliferation with 5-Bromo-2-deoxyuridine (BrdU) assay and flow cytometry. PKC, JNK and p38 expression levels were analyzed by Western blot. Specificity was maintained by employing specific inhibitors; (GF109203X for PKC, SP600125 for JNK and SB203580 for p38MAPK), in some experiments. Results: Optimum proliferation was observed at 5% equibiaxial stretch (BrdU: 0.837 ± 0.026 (control) to 1.462 ± 0.023)%, (P < 0.05) and apoptotic cell death rate decreased from 16.4 ± 0.21% (control) to 4.5 ± 0.13% (P < 0.05) applied at 0.1 Hz. Expression of PKC was upregulated with slight increase in JNK and no change in p38MAPK after application of stretch. Inhibition had effects on proliferation (1.075 ± 0.024, P < 0.05 GF109203X); (1.418 ± 0.021, P > 0.05 SP600125) and (1.461 ± 0.01, P > 0.05 SB203580). These findings show that mechanical stretch can promote magnitude-dependent proliferative modulation through PKC and possibly JNK but not via p38MAPK in hBSMCs.

  3. Theoretical study of the C-H/O-H stretching vibrations in malonaldehyde

    Science.gov (United States)

    Pitsevich, G. A.; Malevich, A. E.; Kozlovskaya, E. N.; Doroshenko, I. Yu.; Pogorelov, V. E.; Sablinskas, V.; Balevicius, V.

    2015-06-01

    IR and Raman spectra of the malonaldehyde molecule and its deuterated analogues were calculated in the B3LYP/cc-pVQZ approximation. Anharmonicity effects were taken into account both in the context of a standard model of the second order perturbation theory and by constructing the potential energy surfaces (PES) with a limited number of dimensions using the Cartesian coordinates of the hydroxyl hydrogen atom and the stretching coordinates of С-Н, C-D, O-H, and O-D bonds. It was shown that in each of the two equivalent forms of the molecule, besides the global minimum, an additional local minimum at the PES is formed with the energy more than 3000 cm-1 higher than the energy in the global minimum. Calculations carried out by constructing the 2D and 3D PESs indicate a high anharmonicity level and multiple manifestations of the stretching О-Н vibrations, despite the fact that the model used does not take into account the splitting of the ground-state and excited vibrational energy levels. In particular, the vibration with the frequency 3258 cm-1 may be associated with proton transfer to the region of a local minimum of energy. Comparing the results obtained with the experimental data presented in the literature allowed us to propose a new variant of bands assignments in IR and Raman spectra of the molecule in the spectral region 2500-3500 cm-1.

  4. Acute effect of different stretching methods on Illinois agility test in soccer players.

    Science.gov (United States)

    Amiri-Khorasani, Mohammadtaghi; Sahebozamani, Mansour; Tabrizi, Kourosh G; Yusof, Ashril B

    2010-10-01

    The purpose of this study was to examine the effects of static, dynamic, and the combination of static and dynamic stretching within a pre-exercise warm-up on the Illinois agility test (IAT) in soccer players. Nineteen professional soccer players (age = 22.5 ± 2.5 years, height = 1.79 ± 0.003 m, body mass = 74.8 ± 10.9 kg) were tested for agility performance using the IAT after different warm-up protocols consisting of static, dynamic, combined stretching, and no stretching. The players were subgrouped into less and more experienced players (5.12 ± 0.83 and 8.18 ± 1.16 years, respectively). There were significant decreases in agility time after no stretching, among no stretching vs. static stretching; after dynamic stretching, among static vs. dynamic stretching; and after dynamic stretching, among dynamic vs. combined stretching during warm-ups for the agility: mean ± SD data were 14.18 ± 0.66 seconds (no stretch), 14.90 ± 0.38 seconds (static), 13.95 ± 0.32 seconds (dynamic), and 14.50 ± 0.35 seconds (combined). There was significant difference between less and more experienced players after no stretching and dynamic stretching. There was significant decrease in agility time following dynamic stretching vs. static stretching in both less and more experienced players. Static stretching does not appear to be detrimental to agility performance when combined with dynamic warm-up for professional soccer players. However, dynamic stretching during the warm-up was most effective as preparation for agility performance. The data from this study suggest that more experienced players demonstrate better agility skills due to years of training and playing soccer.

  5. Acute effects of constant torque and constant angle stretching on the muscle and tendon tissue properties.

    Science.gov (United States)

    Konrad, Andreas; Budini, Francesco; Tilp, Markus

    2017-08-01

    Static stretching induces acute structural changes of the muscle-tendon unit (MTU) that are related to the intensity or duration of stretching. It has been reported that stretching with a constant torque (CT) leads to greater joint range of motion changes than stretching with a constant angle (CA). Whether or not this difference is due to different structural changes of the MTUs of the lower leg and ankle plantar flexors is not known. Therefore, the purpose of this study was to compare the acute effects of single CA and CT stretching on various muscle and tendon mechanical properties. Seventeen young, healthy volunteers were tested on two separate days using either CT or CA stretching (4 × 30 s each). Before and after stretching, dorsiflexion range of motion (RoM), passive resistive torque (PRT), and maximum voluntary contraction (MVC) were measured with a dynamometer. Ultrasonography of the medial gastrocnemius (GM) muscle-tendon junction (MTJ) displacement allowed us to determine the length changes in the tendon and muscle, respectively, and hence to calculate their stiffness. Maximum dorsiflexion increased while PRT, muscle-tendon stiffness, and muscle stiffness decreased following both CA and CT stretching. There was a greater increase in RoM following CT stretching compared to CA stretching. Moreover, the decline in PRT was greater during CT stretching compared to CA stretching. As expected, several functional adaptations (RoM, PRT) were different between CT and CA stretching due to the higher intensity of CT stretching. However, no structural differences in the adaptations to the stretching modalities could be detected. We suggest that the different functional adaptations between CA and CT stretching are the consequence of different adaptations in the perception of stretch and pain.

  6. Effects of diaphragm stretching on posterior chain muscle kinematics and rib cage and abdominal excursion: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Francisco J. González-Álvarez

    2016-01-01

    Full Text Available ABSTRACT Background Few studies have explored the effects of stretching techniques on diaphragm and spine kinematics. Objective To determine whether the application of diaphragm stretching resulted in changes in posterior chain muscle kinematics and ribcage and abdominal excursion in healthy subjects. Method Eighty healthy adults were included in this randomized clinical trial. Participants were randomized into two groups: the experimental group, which received a diaphragmatic stretching technique, or the placebo group, which received a sham-ultrasound procedure. The duration of the technique, the position of participants, and the therapist who applied the technique were the same for both treatments. Participant assessment (cervical range of movement, lumbar flexibility, flexibility of the posterior chain, and rib cage and abdominal excursion was performed at baseline and immediately after the intervention by a blinded assessor. Results The mean between-group difference [95% CI] for the ribcage excursion after technique at xiphoid level was 2.48 [0.97 to 3.99], which shows significant differences in this outcome. The remaining between-group analysis showed significant differences in cervical extension, right and left flexion, flexibility of the posterior chain, and ribcage excursion at xiphoid level (p<0.05 in favor of the experimental group. Conclusion Diaphragm stretching generates a significant improvement in cervical extension, right and left cervical flexion, flexibility of the posterior chain, and ribcage excursion at xiphoid level compared to a placebo technique in healthy adults.

  7. The Effect of Thoracic Joint Mobilization and Self-stretching Exercise on Pulmonary Functions of Patients with Chronic Neck Pain.

    Science.gov (United States)

    Hwangbo, Pil-Neo; Hwangbo, Gak; Park, Jungseo; Lee, Sangyong

    2014-11-01

    [Purpose] The objective of this study was to determine the effect of thoracic joint mobilization and self-stretching exercise on the pulmonary functions of patients with chronic neck pain. [Subjects] The present study was performed with 34 patients with chronic neck pain featuring thoracic kyphosis; we divided them into a thoracic joint mobilization group (TJMG, n = 11), self-stretching exercise group (SSEG, n = 11), and thoracic joint mobilization and self-stretching exercise group (TJMSSEG, n = 12). [Methods] Treatments and exercise were conducted three times a week for six weeks in TJMG, SSEG, and TJMSSEG; the subjects' pulmonary functions in terms of forced vital capacity (FVC), forced expiratory volume at one second (FEV1), and peak expiratory flow (PEF) were measured using CardioTouch equipment. [Results] Comparisons of the individuals within each of the TJMG, SSEG, and TJMSSEG showed that all of FVC, FEV1, and PEF increased significantly; Comparisons within each of the showed that FVC, FEV1, and PEF increased significantly. Among the study groups, FVC was significantly higher in TJMSSEG than in TJMG after six weeks; FEV1 was significantly higher in TJMSSEG than in TJMG and SSEG after four and six weeks; and PEF was significantly higher in TJMSSEG than in TJMG and SSEG after six weeks. [Conclusion] The study results indicate that thoracic joint mobilization and self-stretching exercise are effective interventions for increasing FVC, FEV1, and PEF among pulmonary functions.

  8. Effect of frequency of static stretching on flexibility, hamstring tightness and electromyographic activity

    Directory of Open Access Journals (Sweden)

    A.P. Marques

    2009-10-01

    Full Text Available We compared the effect of the number of weekly repetitions of a static stretching program on the flexibility, hamstring tightness and electromyographic activity of the hamstring and of the triceps surae muscles. Thirty-one healthy subjects with hamstring tightness, defined as the inability to perform total knee extension, and shortened triceps surae, defined by a tibiotarsal angle wider than 90° during trunk flexion, were divided into three groups: G1 performed the stretching exercises once a week; G2, three times a week, and G3, five times a week. The parameters were determined before and after the stretching program. Flexibility improved in all groups after intervention, from 7.65 ± 10.38 to 3.67 ± 12.08 in G1, from 10.73 ± 12.07 to 0.77 ± 10.45 in G2, and from 14.20 ± 10.75 to 6.85 ± 12.19 cm in G3 (P < 0.05 for all comparisons. The increase in flexibility was higher in G2 than in G1 (P = 0.018, while G2 and G3 showed no significant difference (G1: 4 ± 2.17, G2: 10 ± 5.27; G3: 7.5 ± 4.77 cm. Hamstring tightness improved in all groups, from 37.90 ± 6.44 to 29 ± 11.65 in G1, from 39.82 ± 9.63 to 21.91 ± 8.40 in G2, and from 37.20 ± 6.63 to 26.10 ± 5.72° in G3 (P < 0.05 for all comparisons. During stretching, a statistically significant difference was observed in electromyographic activity of biceps femoris muscle between G1 and G3 (P = 0.048 and G2 and G3 (P = 0.0009. No significant differences were found in electromyographic activity during maximal isometric contraction. Stretching exercises performed three times a week were sufficient to improve flexibility and range of motion compared to subjects exercising once a week, with results similar to those of subjects who exercised five times a week.

  9. Acute Effect of Static Stretching Exercise on Arterial Stiffness in Healthy Young Adults.

    Science.gov (United States)

    Yamato, Yosuke; Hasegawa, Natsuki; Sato, Koji; Hamaoka, Takafumi; Ogoh, Shigehiko; Iemitsu, Motoyuki

    2016-10-01

    Habitual stretching exercise increases carotid arterial compliance, and acute stretching exercise increases arterial compliance in patients with myocardial infarction. However, it is not known whether this arterial adaptation is sustained after exercise. The aim of this study was to examine the effect of a single bout of stretching exercise on the time course of systemic, central, and peripheral arterial stiffness in healthy young subjects. Twenty-six healthy young men performed static stretching exercise involving the entire body (trunk, upper limb, and lower limb) for 40 mins. Pulse-wave velocity (PWV; an index of arterial stiffness), blood pressure, and heart rate were measured before and 0, 15, 30, and 60 mins after stretching exercise. Femoral-ankle PWV and brachial-ankle PWV were reduced relative to baseline 15 and 30 mins after acute stretching (P stretch stimulation may result in chronic high arterial compliance, although a single bout of stretch exercise acutely affects arterial compliance.

  10. Number of repetition after different rest intervals between static stretching and resistance training

    Directory of Open Access Journals (Sweden)

    H. Dias

    2017-09-01

    Conclusions: Therefore, 30-minute interval between static stretching and resistance exercises was needed to achieve greater repetition performance. Thus, static stretching for lower limbs may be avoided before a resistance training session.

  11. Effects of aerobic training combined with respiratory muscle stretching on the functional exercise capacity and thoracoabdominal kinematics in patients with COPD: a randomized and controlled trial.

    Science.gov (United States)

    Wada, Juliano T; Borges-Santos, Erickson; Porras, Desiderio Cano; Paisani, Denise M; Cukier, Alberto; Lunardi, Adriana C; Carvalho, Celso Rf

    2016-01-01

    Patients with COPD present a major recruitment of the inspiratory muscles, predisposing to chest incoordination, increasing the degree of dyspnea and impairing their exercise capacity. Stretching techniques could decrease the respiratory muscle activity and improve their contractile capacity; however, the systemic effects of stretching remain unknown. The aim of this study was to evaluate the effects of aerobic training combined with respiratory muscle stretching on functional exercise capacity and thoracoabdominal kinematics in patients with COPD. This study was a randomized and controlled trial. A total of 30 patients were allocated to a treatment group (TG) or a control group (CG; n=15, each group). The TG was engaged in respiratory muscle stretching and the CG in upper and lower limb muscle stretching. Both groups performed 24 sessions (twice a week, 12 weeks) of aerobic training. Functional exercise capacity (6-minute walk test), thoracoabdominal kinematics (optoelectronic plethysmography), and respiratory muscle activity (surface electromyography) were evaluated during exercise. Analysis of covariance was used to compare the groups at a significance level of 5%. After the intervention, the TG showed improved abdominal (ABD) contribution, compartmental volume, mobility, and functional exercise capacity with decreased dyspnea when compared with the CG ( P stretching increases the functional exercise capacity with decreased dyspnea in patients with COPD. These effects are associated with an increased efficacy of the respiratory muscles and participation of the ABD compartment.

  12. Comparing the effects of aerobic and stretching exercises on the intensity of primary dysmenorrhea in the students of universities of bushehr.

    Directory of Open Access Journals (Sweden)

    Farideh Vaziri

    2015-03-01

    Full Text Available To compare the effects of aerobic and stretching exercises on severity of primary dysmenorrhea.This randomized clinical trial was conducted on 105 female students who were suffering from primary dysmenorrhea. The participants were divided into aerobic exercise, stretching exercise, and control groups. The two intervention groups did the exercises three times a week for eight weeks (two menstrual cycles. The intensity of dysmenorrhea was determined using a modified questionnaire that assessed several symptoms of dysmenorrhea. After all, the data were compared between and within groups through analysis of variance.Before the intervention, the mean intensity of dysmenorrhea was 40.38 ± 5.5, 37.40 ± 3.8, and 38.45±3.3 in aerobic, stretching, and control groups, respectively, but the difference was not statistically significant. After the intervention, however, a significant difference was found among the three groups regarding the mean intensity of dysmenorrhea in the first and second menstrual cycles. Also, a significant difference was observed between the aerobic group and the control group as well as between the stretching group and the control group. Within group comparisons showed a significant difference in the aerobic and the stretching group before and after the interventions. However, no such difference was observed in control group.Both aerobic and stretching exercises were effective in reducing the severity of dysmenorrhea. Therefore, women could choose one of these two methods with regard to their interest and lifestyle.

  13. DNA-cisplatin binding mechanism peculiarities studied with single molecule stretching experiments

    Science.gov (United States)

    Crisafuli, F. A. P.; Cesconetto, E. C.; Ramos, E. B.; Rocha, M. S.

    2012-02-01

    We propose a method to determine the DNA-cisplatin binding mechanism peculiarities by monitoring the mechanical properties of these complexes. To accomplish this task, we have performed single molecule stretching experiments by using optical tweezers, from which the persistence and contour lengths of the complexes can be promptly measured. The persistence length of the complexes as a function of the drug total concentration in the sample was used to deduce the binding data, from which we show that cisplatin binds cooperatively to the DNA molecule, a point which so far has not been stressed in binding equilibrium studies of this ligand.

  14. Relationship between the degree of inhibited stretch reflex activities of the wrist flexor and reaction time during quick extension movements.

    Science.gov (United States)

    Kizuka, T; Asami, T; Tanii, K

    1997-08-01

    It has been reported that stretch reflex responses, including the long latency component, are modulated by motor preparation for the direction and type of movement. In the present study, human subjects were required to make a reaction movement in the direction of the wrist extension following a muscle stretch to the wrist flexor, and we investigated the relationship between the modulation of reflex activities of the wrist flexor and the length of reaction time (premotor time) of the wrist extensor. Twenty-five healthy males, ranging in age from 20 to 28, participated in the experiments. A DC torque motor was used to evoke the reflex EMG responses on the flexor. Averaging the rectified EMG, recorded with the surface electrodes over the flexor, showed short and long latency reflexes (M1 and M2 components) in response to the muscle stretch. For all subjects, the amplitudes of the reflex components during the extension reaction movement decreased, compared to those amplitudes in the non-reaction tasks. The decrease in the M2 component, which is considered a transcortical reflex, was significantly larger than the decrease in the M1 component, which is a spinal reflex. Moreover, there were correlations between reaction time to muscle stretch and the degree of decrease in reflex activities with the extension reaction (r = 0.652 for M1, r = 0.813 for M2, P motor control required to perform quick movements.

  15. Enhancing Crystallinity and Orientation by Hot-Stretching to Improve the Mechanical Properties of Electrospun Partially Aligned Polyacrylonitrile (PAN) Nanocomposites

    Science.gov (United States)

    Song, Zhenyu; Hou, Xiaoxiao; Zhang, Liqun; Wu, Sizhu

    2011-01-01

    Partially aligned polyacrylonitrile (PAN)-based nanofibers were electrospun from PAN and PAN/single-walled carbon nanotubes (SWNTs) in a solution of dimethylformamide (DMF) to make the nanofiber composites. The as-spun nanofibers were then hot-stretched in the oven to enhance its orientation and crystallinity. With the introduction of SWNTs and by the hot-stretched process, the mechanical properties will be enhanced correspondingly. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray scattering (XRD), differential scanning calorimetry (DSC), and the tensile test were used to characterize the microstructure and performances of the nanofibers. The orientation and crystallinity of the as-spun and hot-stretched nanofibers confirmed by X-ray have increased. Differential scanning calorimetry showed that the glass transition temperature of PAN increased about 3 °C by an addition of 0.75 wt% SWNTs indicating a strong interfacial interaction between PAN and SWNTs. The tensile strength and the modulus of the nanofibers increased revealing significant load transfer across the nanotube-matrix interface. For PAN nanofibers, the improved fiber alignment, orientation and crystallinity resulted in enhanced mechanical properties, such as the tensile strength and modulus of the nanofibers. It was concluded that the hot-stretched nanofiber and the PAN/SWNTs nanofibers can be used as a potential precursor to produce high-performance nanocomposites. PMID:28879944

  16. Enhancing Crystallinity and Orientation by Hot-Stretching to Improve the Mechanical Properties of Electrospun Partially Aligned Polyacrylonitrile (PAN Nanocomposites

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Hou

    2011-04-01

    Full Text Available Partially aligned polyacrylonitrile (PAN-based nanofibers were electrospun from PAN and PAN/single-walled carbon nanotubes (SWNTs in a solution of dimethylformamide (DMF to make the nanofiber composites. The as-spun nanofibers were then hot-stretched in the oven to enhance its orientation and crystallinity. With the introduction of SWNTs and by the hot-stretched process, the mechanical properties will be enhanced correspondingly. Scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray scattering (XRD, differential scanning calorimetry (DSC, and the tensile test were used to characterize the microstructure and performances of the nanofibers. The orientation and crystallinity of the as-spun and hot-stretched nanofibers confirmed by X-ray have increased. Differential scanning calorimetry showed that the glass transition temperature of PAN increased about 3 °C by an addition of 0.75 wt% SWNTs indicating a strong interfacial interaction between PAN and SWNTs. The tensile strength and the modulus of the nanofibers increased revealing significant load transfer across the nanotube-matrix interface. For PAN nanofibers, the improved fiber alignment, orientation and crystallinity resulted in enhanced mechanical properties, such as the tensile strength and modulus of the nanofibers. It was concluded that the hot-stretched nanofiber and the PAN/SWNTs nanofibers can be used as a potential precursor to produce high-performance nanocomposites.

  17. Enhancing Crystallinity and Orientation by Hot-Stretching to Improve the Mechanical Properties of Electrospun Partially Aligned Polyacrylonitrile (PAN) Nanocomposites.

    Science.gov (United States)

    Song, Zhenyu; Hou, Xiaoxiao; Zhang, Liqun; Wu, Sizhu

    2011-04-06

    Partially aligned polyacrylonitrile (PAN)-based nanofibers were electrospun from PAN and PAN/single-walled carbon nanotubes (SWNTs) in a solution of dimethylformamide (DMF) to make the nanofiber composites. The as-spun nanofibers were then hot-stretched in the oven to enhance its orientation and crystallinity. With the introduction of SWNTs and by the hot-stretched process, the mechanical properties will be enhanced correspondingly. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray scattering (XRD), differential scanning calorimetry (DSC), and the tensile test were used to characterize the microstructure and performances of the nanofibers. The orientation and crystallinity of the as-spun and hot-stretched nanofibers confirmed by X-ray have increased. Differential scanning calorimetry showed that the glass transition temperature of PAN increased about 3 °C by an addition of 0.75 wt% SWNTs indicating a strong interfacial interaction between PAN and SWNTs. The tensile strength and the modulus of the nanofibers increased revealing significant load transfer across the nanotube-matrix interface. For PAN nanofibers, the improved fiber alignment, orientation and crystallinity resulted in enhanced mechanical properties, such as the tensile strength and modulus of the nanofibers. It was concluded that the hot-stretched nanofiber and the PAN/SWNTs nanofibers can be used as a potential precursor to produce high-performance nanocomposites.

  18. Spasticity Measurement Based on Tonic Stretch Reflex Threshold in Children with Cerebral Palsy Using the PediAnklebot

    Directory of Open Access Journals (Sweden)

    Marco Germanotta

    2017-05-01

    Full Text Available Nowadays, objective measures are becoming prominent in spasticity assessment, to overcome limitations of clinical scales. Among others, Tonic Stretch Reflex Threshold (TSRT showed promising results. Previous studies demonstrated the validity and reliability of TSRT in spasticity assessment at elbow and ankle joints in adults. Purposes of the present study were to assess: (i the feasibility of measuring TSRT to evaluate spasticity at the ankle joint in children with Cerebral Palsy (CP, and (ii the correlation between objective measures and clinical scores. A mechatronic device, the pediAnklebot, was used to impose 50 passive stretches to the ankle of 10 children with CP and 3 healthy children, to elicit muscles response at 5 different velocities. Surface electromyography, angles, and angular velocities were recorded to compute dynamic stretch reflex threshold; TSRT was computed with a linear regression through angles and angular velocities. TSRTs for the most affected side of children with CP resulted into the biomechanical range (95.7 ± 12.9° and 86.7 ± 17.4° for Medial and Lateral Gastrocnemius, and 75.9 ± 12.5° for Tibialis Anterior. In three patients, the stretch reflex was not elicited in the less affected side. TSRTs were outside the biomechanical range in healthy children. However, no correlation was found between clinical scores and TSRT values. Here, we demonstrated the capability of TSRT to discriminate between spastic and non-spastic muscles, while no significant outcomes were found for the dorsiflexor muscle.

  19. Electromyography characterization of stretch responses in hemiparetic stroke patients and their relationship with the Modified Ashworth scale.

    Science.gov (United States)

    Cooper, A; Musa, I M; van Deursen, R; Wiles, C M

    2005-10-01

    To determine the validity of the Modified Ashworth Scale as a measure of spasticity by determining its relationship to surface electromyography activity and contracture. A controlled study of hemiparetic stroke patients with spasticity. A physiotherapy department in a secondary care hospital. Thirty-one stroke patients and 20 healthy volunteers. The resistance to passive movement around the knee and ankle of the affected and unaffected legs was rated using the Modified Ashworth Scale. Passive range of movement was measured with a goniometer. Surface electromyography recordings of four lower limb muscles were taken during passive stretches of the knee and ankle. Hemiparetic patients produced surface electromyography responses to stretch that were of greater amplitude (unaffected limbs: mean = 25.82 mV (43.85), affected limbs: mean = 24.77 mV (35.46)) than those of healthy volunteers (mean = 15.85 (29.96)). The affected muscles of hemiparetic patients were more likely to produce surface electromyography responses to stretch of a sustained duration (45% of cases) compared with unaffected limbs (24% of cases) and those of healthy volunteers (16% of cases). The Modified Ashworth Scale showed a positive correlation with the magnitude (p Ashworth Scale were associated with contracture (p Ashworth Scale reflects spasticity in terms of surface electromyography stretch responses produced by passive movement, but the relationship of spasticity to contracture remains unclear.

  20. Effects of proprioceptive neuromuscular facilitation stretching and deep-breathing exercises on upper extremity lymphedema in stroke patients.

    Science.gov (United States)

    Hwang, Woon Taek; Jeong, Yeon-Jae; Kim, Seong-Yeol; Jeong, Yeon-Gyu

    2016-12-01

    [Purpose] The purpose of this study was to determine the effects of deep-breathing and proprioceptive neuromuscular facilitation stretching exercises on upper limb lymphedema in stroke patients. [Subjects and Methods] The study consisted of 10 patients with lymphedema that had occurred after stroke. Neurodevelopmental treatment was applied in the same manner as that used for the existing treatment. The subjects performed deep-breathing and stretching exercises three times per week for 4 weeks (12 sessions total). Body water volume in the upper limbs was measured before and after exercise by using an InBody S10 analyzer. [Results] Performance of deep-breathing and stretching exercises significantly reduced body water volume in both the affected and unaffected arms. The extracellular-to-total cellular fluid volume ratio in the affected arm improved to 0.379 after exercise, although this change was not significant. [Conclusion] The results of the present study show that deep-breathing and proprioceptive neuromuscular facilitation stretching exercises reduce upper extremity lymphedema in stroke patients.

  1. Directing Spinal Cord Plasticity: The Impact of Stretch Therapy on Functional Recovery after Spinal Cord Injury

    Science.gov (United States)

    2013-10-01

    weight. 15. SUBJECT TERMS Spinal cord injury, stretching, physical therapy , rehabilitation, locomotor recovery 16. SECURITY CLASSIFICATION OF...David S. K. Magnuson, PhD. University of Louisville. Introduction: This research focuses on the impact of stretching ( physical therapy maneuvers...lesions. Physical therapists use stretching maneuvers to maintain extensibility of soft tissues and to manage spasticity . Previous studies in our lab

  2. Can Stretching Prior to Exercise and Sports Improve Performance and Prevent Injury?

    Science.gov (United States)

    Bracko, Michael R.

    2002-01-01

    Examines data from research on stretching as it relates to enhanced performance and injury prevention so that fitness, exercise, and sports performance professionals can make informed decisions about stretching programs for clients. The paper notes that stretching is a misunderstood component of fitness and sports training. Few studies show…

  3. DNA analysis by single molecule stretching in nanofluidic biochips

    DEFF Research Database (Denmark)

    Abad, E.; Juarros, A.; Retolaza, A.

    2011-01-01

    Stretching single DNA molecules by confinement in nanofluidic channels has attracted a great interest during the last few years as a DNA analysis tool. We have designed and fabricated a sealed micro/nanofluidic device for DNA stretching applications, based on the use of the high throughput Nano......Imprint Lithography (NIL) technology combined with a conventional anodic bonding of the silicon base and Pyrex cover. Using this chip, we have performed single molecule imaging on a bench-top fluorescent microscope system. Lambda phage DNA was used as a model sample to characterize the chip. Single molecules of λ...... a method to determining DNA size. The results of this work prove that the developed fabrication process is a good alternative for the fabrication of single molecule DNA biochips and it allows developing a variety of innovative bio/chemical sensors based on single-molecule DNA sequencing devices....

  4. Progressive muscle relaxation, yoga stretching, and ABC relaxation theory.

    Science.gov (United States)

    Ghoncheh, Shahyad; Smith, Jonathan C

    2004-01-01

    This study compared the psychological effects of progressive muscle relaxation (PMR) and yoga stretching (hatha) exercises. Forty participants were randomly divided into two groups and taught PMR or yoga stretching exercises. Both groups practiced once a week for five weeks and were given the Smith Relaxation States Inventory before and after each session. As hypothesized, practitioners of PMR displayed higher levels of relaxation states (R-States) Physical Relaxation and Disengagement at Week 4 and higher levels of Mental Quiet and Joy as a posttraining aftereffect at Week 5. Contrary to what was hypothesized, groups did not display different levels of R-States Energized or Aware. Results suggest the value of supplementing traditional somatic conceptualizations of relaxation with the psychological approach embodied in ABC relaxation theory. Clinical and research implications are discussed. Copyright 2003 Wiley Periodicals, Inc. J Clin Psychol.

  5. FUZZY BASED CONTRAST STRETCHING FOR MEDICAL IMAGE ENHANCEMENT

    Directory of Open Access Journals (Sweden)

    T.C. Raja Kumar

    2011-07-01

    Full Text Available Contrast Stretching is an important part in medical image processing applications. Contrast is the difference between two adjacent pixels. Fuzzy statistical values are analyzed and better results are produced in the spatial domain of the input image. The histogram mapping produces the resultant image with less impulsive noise and smooth nature. The probabilities of gray values are generated and the fuzzy set is determined from the position of the input image pixel. The result indicates the good performance of the proposed fuzzy based stretching. The inverse transform of the real values are mapped with the input image to generate the fuzzy statistics. This approach gives a flexible image enhancement for medical images in the presence of noises.

  6. Convective Flow of Sisko Fluid over a Bidirectional Stretching Surface.

    Science.gov (United States)

    Munir, Asif; Shahzad, Azeem; Khan, Masood

    2015-01-01

    The present investigation focuses the flow and heat transfer characteristics of the steady three-dimensional Sisko fluid driven by a bidirectional stretching sheet. The modeled partial differential equations are reduced to coupled ordinary differential equations by a suitable transformation. The resulting equations are solved numerically by the shooting method using adaptive Runge Kutta algorithm in combination with Newton's method in the domain [0,∞). The numerical results for the velocity and temperature fields are graphically presented and effects of the relevant parameters are discussed in detail. Moreover, the skin-friction coefficient and local Nusselt number for different values of the power-law index and stretching ratio parameter are presented through tabulated data. The numerical results are also verified with the results obtained analytically by the homotopy analysis method (HAM). Additionally, the results are validated with previously published pertinent literature as a limiting case of the problem.

  7. Mechanical stretch modulates cell migration in the lungs.

    Science.gov (United States)

    López-Martínez, Cecilia; Huidobro, Covadonga; Albaiceta, Guillermo M; López-Alonso, Inés

    2018-01-01

    Cell migration is a core process to preserve homeostasis. Release of chemotactic signals induces changes in cell cytoskeleton to facilitate migration. This includes the rearrangement of cytoskeleton, genomic reprogramming and the modification of the surrounding extracellular matrix (ECM) to allow the motion of cells through. In the special case of repair after acute lung injury, cells must migrate while exposed to an increased mechanical stretch caused either by an increased work of breathing or positive-pressure ventilation. Interestingly, the cell response to this increased mechanical load can modify virtually all the mechanisms involved in cell migration. In this review we explore the interplay between stretch and the machinery responsible for cell migration. A translational approach to find new therapies in acute lung injury must take into account these interactions in order to develop effective treatments that promote lung repair.

  8. Effects of spray and stretch on postneedling soreness and sensitivity after dry needling of a latent myofascial trigger point.

    Science.gov (United States)

    Martín-Pintado Zugasti, Aitor; Rodríguez-Fernández, Ángel L; García-Muro, Francisco; López-López, Almudena; Mayoral, Orlando; Mesa-Jiménez, Juan; Fernández-Carnero, Josue

    2014-10-01

    To investigate (1) the effect of spray and stretch versus control on reducing postneedling soreness of 1 latent myofascial trigger point (MTrP) and (2) whether higher levels of psychological distress are associated with increased postneedling pain intensity. A 72-hour follow-up, single-blind randomized controlled trial. University community. Healthy volunteers (N=70; 40 men, 30 women) aged 18 to 36 years (mean age, 21±4y) with latent MTrP in 1 upper trapezius muscle. All subjects received a dry needling application over the upper trapezius muscle. Then, participants were randomly divided into 2 groups: an intervention group, which received spray and stretch over the needled trapezius muscle, and a control group, which did not receive any intervention. Visual analog scale (at postneedling, posttreatment, and 6, 12, 24, 48, and 72h after needling), pressure pain threshold (at preneedling, postneedling, and 24 and 48h after needling). Psychological distress was evaluated by using the Symptom Checklist-90-Revised. Repeated-measures analysis of variance demonstrated a significant interaction between group and time (F3,204.8=3.19; P.05). Repeated measures of covariance showed that none of the psychological covariates affected these results. Somatization, anxiety, interpersonal sensitivity, and hostility were significantly correlated (P<.05) with postneedling pain intensity. Repeated-measures analysis of variance did not show a significant effect of spray and stretch on mechanical hyperalgesia (F2.6,175=1.9; P=.131; ηp(2)=.02). The spray and stretch had a short-term (<6h) effect in reducing postneedling soreness of a latent MTrP. Pressure pain threshold did not significantly change after spray and stretch. Psychological factors are related to postneedling pain. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  9. Phase transitions in single macromolecules: Loop-stretch transition versus loop adsorption transition in end-grafted polymer chains

    Science.gov (United States)

    Zhang, Shuangshuang; Qi, Shuanhu; Klushin, Leonid I.; Skvortsov, Alexander M.; Yan, Dadong; Schmid, Friederike

    2018-01-01

    We use Brownian dynamics simulations and analytical theory to compare two prominent types of single molecule transitions. One is the adsorption transition of a loop (a chain with two ends bound to an attractive substrate) driven by an attraction parameter ɛ and the other is the loop-stretch transition in a chain with one end attached to a repulsive substrate, driven by an external end-force F applied to the free end. Specifically, we compare the behavior of the respective order parameters of the transitions, i.e., the mean number of surface contacts in the case of the adsorption transition and the mean position of the chain end in the case of the loop-stretch transition. Close to the transition points, both the static behavior and the dynamic behavior of chains with different length N are very well described by a scaling ansatz with the scaling parameters (ɛ - ɛ*)Nϕ (adsorption transition) and (F - F*)Nν (loop-stretch transition), respectively, where ϕ is the crossover exponent of the adsorption transition and ν is the Flory exponent. We show that both the loop-stretch and the loop adsorption transitions provide an exceptional opportunity to construct explicit analytical expressions for the crossover functions which perfectly describe all simulation results on static properties in the finite-size scaling regime. Explicit crossover functions are based on the ansatz for the analytical form of the order parameter distributions at the respective transition points. In contrast to the close similarity in equilibrium static behavior, the dynamic relaxation at the two transitions shows qualitative differences, especially in the strongly ordered regimes. This is attributed to the fact that the surface contact dynamics in a strongly adsorbed chain is governed by local processes, whereas the end height relaxation of a strongly stretched chain involves the full spectrum of Rouse modes.

  10. Device for stretching tapes or cables intended for manipulators

    International Nuclear Information System (INIS)

    Baudoin, J.-C.; Oger, Robert.

    1975-01-01

    The invention relates to a device for stretching tapes (or cables) intended for remote handling devices. Said equipment consists of a spring system continuously applying a constant tensile stress to said tapes (or cables) in view of taking up the slack in the latter. Said spring system is fastened to a supporting bar able to be rigidly connected to a member of the remote handling device [fr

  11. Effect of hexane treatment and uniaxial stretching on bending ...

    African Journals Online (AJOL)

    ... β31, defined as the bending piezoelectric stress constant, was calculated. After hexane treatment and uniaxial stretching of the PVDF film, the value of β31 was 5.75 mV/m and 8.00 mV/m for draw ratio of 1.5 and 2.5 was recorded. Fourier transform Infra-red (FTIR) spectrophotometry was used for structural investigations.

  12. Growth on demand: reviewing the mechanobiology of stretched skin.

    Science.gov (United States)

    Zöllner, Alexander M; Holland, Maria A; Honda, Kord S; Gosain, Arun K; Kuhl, Ellen

    2013-12-01

    Skin is a highly dynamic, autoregulated, living system that responds to mechanical stretch through a net gain in skin surface area. Tissue expansion uses the concept of controlled overstretch to grow extra skin for defect repair in situ. While the short-term mechanics of stretched skin have been studied intensely by testing explanted tissue samples ex vivo, we know very little about the long-term biomechanics and mechanobiology of living skin in vivo. Here we explore the long-term effects of mechanical stretch on the characteristics of living skin using a mathematical model for skin growth. We review the molecular mechanisms by which skin responds to mechanical loading and model their effects collectively in a single scalar-valued internal variable, the surface area growth. This allows us to adopt a continuum model for growing skin based on the multiplicative decomposition of the deformation gradient into a reversible elastic and an irreversible growth part. To demonstrate the inherent modularity of this approach, we implement growth as a user-defined constitutive subroutine into the general purpose implicit finite element program Abaqus/Standard. To illustrate the features of the model, we simulate the controlled area growth of skin in response to tissue expansion with multiple filling points in time. Our results demonstrate that the field theories of continuum mechanics can reliably predict the manipulation of thin biological membranes through mechanical overstretch. Our model could serve as a valuable tool to rationalize clinical process parameters such as expander geometry, expander size, filling volume, filling pressure, and inflation timing to minimize tissue necrosis and maximize patient comfort in plastic and reconstructive surgery. While initially developed for growing skin, our model can easily be generalized to arbitrary biological structures to explore the physiology and pathology of stretch-induced growth of other living systems such as hearts

  13. DEVELOPMENT OF DEFORMATION STRIPS WHILE STRETCHING OF CYLINDRICAL SAMPLES

    Directory of Open Access Journals (Sweden)

    Y. V. Vasilevich

    2011-01-01

    Full Text Available Deformation strips have been experimentally revealed and described while stretching of cylindrical samples by means of computer thermography. It has been established that temperature of shift strip surface grows smoothly up to the stage of crack origin in material defect. Sharp growth of surface temperature occurs when tensile stresses reach tensile strength. Change in surface temperature occurs wavy after destruction (while cooling the sample. Processes of material destruction origin and development  characterize temperature changes in deformation strips.

  14. Statistical analysis of stretch film production process capabilities

    OpenAIRE

    Kovačić, Goran; Kondić, Živko

    2012-01-01

    The basic concept of statistical process control is based on the comparison of data collected from the process with calculated control limits and conclusions about the process based on the above. This process is recognized as a modern method for the analysis of process capabilities over different capability indexes. This paper describes the application of this method in monitoring and analysis of stretch film production process capabilities.

  15. A discrete electromechanical model for human cardiac tissue: effects of stretch-activated currents and stretch conditions on restitution properties and spiral wave dynamics.

    Directory of Open Access Journals (Sweden)

    Louis D Weise

    Full Text Available We introduce an electromechanical model for human cardiac tissue which couples a biophysical model of cardiac excitation (Tusscher, Noble, Noble, Panfilov, 2006 and tension development (adjusted Niederer, Hunter, Smith, 2006 model with a discrete elastic mass-lattice model. The equations for the excitation processes are solved with a finite difference approach, and the equations of the mass-lattice model are solved using Verlet integration. This allows the coupled problem to be solved with high numerical resolution. Passive mechanical properties of the mass-lattice model are described by a generalized Hooke's law for finite deformations (Seth material. Active mechanical contraction is initiated by changes of the intracellular calcium concentration, which is a variable of the electrical model. Mechanical deformation feeds back on the electrophysiology via stretch-activated ion channels whose conductivity is controlled by the local stretch of the medium. We apply the model to study how stretch-activated currents affect the action potential shape, restitution properties, and dynamics of spiral waves, under constant stretch, and dynamic stretch caused by active mechanical contraction. We find that stretch conditions substantially affect these properties via stretch-activated currents. In constantly stretched medium, we observe a substantial decrease in conduction velocity, and an increase of action potential duration; whereas, with dynamic stretch, action potential duration is increased only slightly, and the conduction velocity restitution curve becomes biphasic. Moreover, in constantly stretched medium, we find an increase of the core size and period of a spiral wave, but no change in rotation dynamics; in contrast, in the dynamically stretching medium, we observe spiral drift. Our results may be important to understand how altered stretch conditions affect the heart's functioning.

  16. Longitudinal Stretching for Maturation of Vascular Tissues Using Magnetic Forces

    Directory of Open Access Journals (Sweden)

    Timothy R. Olsen

    2016-11-01

    Full Text Available Cellular spheroids were studied to determine their use as “bioinks” in the biofabrication of tissue engineered constructs. Specifically, magnetic forces were used to mediate the cyclic longitudinal stretching of tissues composed of Janus magnetic cellular spheroids (JMCSs, as part of a post-processing method for enhancing the deposition and mechanical properties of an extracellular matrix (ECM. The purpose was to accelerate the conventional tissue maturation process via novel post-processing techniques that accelerate the functional, structural, and mechanical mimicking of native tissues. The results of a forty-day study of JMCSs indicated an expression of collagen I, collagen IV, elastin, and fibronectin, which are important vascular ECM proteins. Most notably, the subsequent exposure of fused tissue sheets composed of JMCSs to magnetic forces did not hinder the production of these key proteins. Quantitative results demonstrate that cyclic longitudinal stretching of the tissue sheets mediated by these magnetic forces increased the Young’s modulus and induced collagen fiber alignment over a seven day period, when compared to statically conditioned controls. Specifically, the elastin and collagen content of these dynamically-conditioned sheets were 35- and three-fold greater, respectively, at seven days compared to the statically-conditioned controls at three days. These findings indicate the potential of using magnetic forces in tissue maturation, specifically through the cyclic longitudinal stretching of tissues.

  17. A Novel Stretch Sensor to Measure Venous Hemodynamics

    Directory of Open Access Journals (Sweden)

    Syrpailyne Wankhar

    2018-07-01

    Full Text Available Chronic venous insufficiency is a debilitating condition causing varicose veins and venous ulcers. The pathophysiology includes reflux and venous obstruction. The diagnosis is often made by clinical examination and confirmed by Venous Doppler studies. Plethysmography helps to quantitatively examine the reflux and diagnose the burden of deep venous pathology to better understand venous hemodynamics, which is not elicited by venous duplex examination alone. However, most of these tests are qualitative, expensive, and not easily available. In this paper, we demonstrate the potential use of a novel stretch sensor in the assessment of venous hemodynamics during different maneuvers by measuring the change in calf circumference. We designed the stretch sensor by using semiconductor strain gauges pasted onto a small metal bar to form a load cell. The elastic and Velcro material attached to the load cell form a belt. It converts the change in limb circumference to a proportional tension (force of distension when placed around the calf muscle. We recorded the change in limb circumference from arrays of stretch sensors by using an in-house data acquisition system. We calculated the venous volume (VV, venous filling index (VFI, ejection fraction (EF and residual venous volume (RVV on two normal subjects and on two patients to assess venous hemodynamics. The values (VV > 60 ml, VFI 60%, RVV 2ml/s, EF 35% in patients were comparable to those reported in the literature.

  18. Cyclic Mechanical Stretch Induced Smooth Muscle Cell Changes in Cerebral Aneurysm Progress by Reducing Collagen Type IV and Collagen Type VI Levels

    Directory of Open Access Journals (Sweden)

    Peixi Liu

    2018-02-01

    Full Text Available Background/Aims: Cerebral aneurysm growth is characterized by continuous structural weakness of local smooth muscle cells, though the mechanism is unclear. In this study, we examine protein changes in cerebral aneurysm and human brain vascular smooth muscle cells after cyclic mechanical stretch. We further explore the relationship between the smooth muscle cell changes and reductions in the levels of collagen types IV and VI. Methods: Saccular cerebral aneurysms (n=10 were collected, and temporal artery samples were used as controls. Quantitative proteomics were analyzed and histopathological changes were examined. Smooth muscle cells were cultured in a flexible silicone chamber and subjected to 15% cyclic mechanical stretch. The effect of stretch on the cell viability, function, gene and protein expression were further studied for the understanding the molecular mechanism of aneurysm development. Results: Proteomics analysis revealed 92 proteins with increased expression and 88 proteins with decreased expression compared to the controls (p<0.05. KEGG pathway analysis showed that the change in focal adhesion and extracellular matrix-receptor interaction, suggesting the involvement of collagen type IV and VI. The aneurysm tissue exhibited fewer smooth muscle cells and lower levels of collagen type IV and VI. Human brain vascular smooth muscle cell culture showed spindle-like cells and obvious smooth muscle cell layer. Cell proteomics analysis showed that decreased expression of 118 proteins and increased expression of 32 proteins in smooth muscle cells after cyclic mechanical stretch. KEGG pathway analysis indicated that focal adhesion and ECM-receptor interaction were involved. After cyclic mechanical stretch, collagen type IV and IV expression were decreased. Moreover, the stretch induced MMP-1 and MMP-3 expression elevation. Conclusion: We demonstrated that collagen type IV and VI were decreased in cerebral aneurysms and continuous cyclic

  19. Comparing the effects of 3 weeks of upper-body vibration training, vibration and stretching, and stretching alone on shoulder flexibility in college-aged men.

    Science.gov (United States)

    Ferguson, Steven L; Kim, Eonho; Seo, Dong-Il; Bemben, Michael G

    2013-12-01

    This study compared the effects of 3 weeks of upper-body vibration training, vibration and stretching, and stretching alone on shoulder flexibility in college-aged men. Twenty-one men were randomly assigned to vibration-stretching (VS; n = 8), vibration only (VO; n = 6), or stretching only (SO; n = 7) groups that trained 3 times per week for 3 weeks. All 3 groups performed 9 total sets of 30-second stretches. The VS group performed four 30-second upper-body vibration exercises and five 30-second upper-body stretching exercises. The VO group performed nine 30-second upper-body vibration exercises. The SO group performed nine 30-second upper-body stretching exercises. Shoulder flexion (SF), shoulder extension (SE), and shoulder transverse extension (STE) were assessed by a Leighton Flexometer and back scratch tests bilaterally (BSR, BSL) were measured via tape measure. A 1-way analysis of variance (ANOVA) evaluated groups at baseline and a 2-way repeated-measures ANOVA evaluated the interventions over time. At baseline, there were no group differences in age, height, or weight. There was a significant (p alone or combined with stretching, is a viable alternative to a standard stretching routine when attempting to increase shoulder flexibility. Adding vibration training to a flexibility regimen may improve the likelihood of regularly performing flexibility sessions because of increased variety.

  20. Contraction-specific differences in maximal muscle power during stretch-shortening cycle movements in elderly males and females

    DEFF Research Database (Denmark)

    Caserotti, Paolo; Aagaard, Per; Simonsen, Erik Bruun

    2001-01-01

    Aging, muscle power, stretch-shortening cycle, eccentric muscle actions, concentric contractions......Aging, muscle power, stretch-shortening cycle, eccentric muscle actions, concentric contractions...

  1. Ca{sup 2+} influx and ATP release mediated by mechanical stretch in human lung fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Naohiko [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Ito, Satoru, E-mail: itori@med.nagoya-u.ac.jp [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Furuya, Kishio [Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Takahara, Norihiro [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Naruse, Keiji [Department of Cardiovascular Physiology, Okayama University Graduate School of Medicine, Okayama 700-8558 (Japan); Aso, Hiromichi; Kondo, Masashi [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Sokabe, Masahiro [Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Hasegawa, Yoshinori [Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan)

    2014-10-10

    Highlights: • Uniaxial stretching activates Ca{sup 2+} signaling in human lung fibroblasts. • Stretch-induced intracellular Ca{sup 2+} elevation is mainly via Ca{sup 2+} influx. • Mechanical strain enhances ATP release from fibroblasts. • Stretch-induced Ca{sup 2+} influx is not mediated by released ATP or actin cytoskeleton. - Abstract: One cause of progressive pulmonary fibrosis is dysregulated wound healing after lung inflammation or damage in patients with idiopathic pulmonary fibrosis and severe acute respiratory distress syndrome. The mechanical forces are considered to regulate pulmonary fibrosis via activation of lung fibroblasts. In this study, the effects of mechanical stretch on the intracellular Ca{sup 2+} concentration ([Ca{sup 2+}]{sub i}) and ATP release were investigated in primary human lung fibroblasts. Uniaxial stretch (10–30% in strain) was applied to fibroblasts cultured in a silicone chamber coated with type I collagen using a stretching apparatus. Following stretching and subsequent unloading, [Ca{sup 2+}]{sub i} transiently increased in a strain-dependent manner. Hypotonic stress, which causes plasma membrane stretching, also transiently increased the [Ca{sup 2+}]{sub i}. The stretch-induced [Ca{sup 2+}]{sub i} elevation was attenuated in Ca{sup 2+}-free solution. In contrast, the increase of [Ca{sup 2+}]{sub i} by a 20% stretch was not inhibited by the inhibitor of stretch-activated channels GsMTx-4, Gd{sup 3+}, ruthenium red, or cytochalasin D. Cyclic stretching induced significant ATP releases from fibroblasts. However, the stretch-induced [Ca{sup 2+}]{sub i} elevation was not inhibited by ATP diphosphohydrolase apyrase or a purinergic receptor antagonist suramin. Taken together, mechanical stretch induces Ca{sup 2+} influx independently of conventional stretch-sensitive ion channels, the actin cytoskeleton, and released ATP.

  2. Muscle and joint responses during and after static stretching performed at different intensities.

    Science.gov (United States)

    Freitas, Sandro R; Andrade, Ricardo J; Larcoupaille, Lilian; Mil-homens, Pedro; Nordez, Antoine

    2015-06-01

    We investigated the effects of plantarflexor static stretching of different intensities on the medial gastrocnemius (GAS) shear elastic modulus, GAS fascicle length and ankle passive torque-angle responses during and after stretching. Participants performed three stretching sessions of different intensities: 40 % (R40) of maximal dorsiflexion range of motion (ROM), 60 % (R60) of ROM, and 80 % (R80) of ROM. Each stretching lasted 10 min. The GAS architecture, GAS shear elastic modulus, ankle passive torque-angle, and muscle activity were assessed before, during, and after the stretching. The absolute and relative (i.e., normalized to the static stretching start value) GAS shear elastic modulus relaxation varied across stretching intensities. The absolute passive torque relaxation varied across intensities (p stretching start value. No significant changes were observed in GAS fascicle length during the stretching (p = 0.93). After stretching, passive torque at a given angle was significantly decreased for R60 [-0.99 ± 0.59 Nm (-6.5 ± 3.8 %), p stretching and post-stretching effect in the GAS shear elastic modulus or ankle passive torque variables. No significant relation was found between the shear elastic modulus and the ankle passive torque responses during and after stretching. The effects of stretching on joint passive torque do not reflect changes in the medial gastrocnemius shear elastic modulus, and these responses to stretching depend on its intensity.

  3. Micropatterning stretched and aligned DNA for sequence-specific nanolithography

    Science.gov (United States)

    Petit, Cecilia Anna Paulette

    Techniques for fabricating nanostructured materials can be categorized as either "top-down" or "bottom-up". Top-down techniques use lithography and contact printing to create patterned surfaces and microfluidic channels that can corral and organize nanoscale structures, such as molecules and nanorods in contrast; bottom-up techniques use self-assembly or molecular recognition to direct the organization of materials. A central goal in nanotechnology is the integration of bottom-up and top-down assembly strategies for materials development, device design; and process integration. With this goal in mind, we have developed strategies that will allow this integration by using DNA as a template for nanofabrication; two top-down approaches allow the placement of these templates, while the bottom-up technique uses the specific sequence of bases to pattern materials along each strand of DNA. Our first top-down approach, termed combing of molecules in microchannels (COMMIC), produces microscopic patterns of stretched and aligned molecules of DNA on surfaces. This process consists of passing an air-water interface over end adsorbed molecules inside microfabricated channels. The geometry of the microchannel directs the placement of the DNA molecules, while the geometry of the airwater interface directs the local orientation and curvature of the molecules. We developed another top-down strategy for creating micropatterns of stretched and aligned DNA using surface chemistry. Because DNA stretching occurs on hydrophobic surfaces, this technique uses photolithography to pattern vinyl-terminated silanes on glass When these surface-, are immersed in DNA solution, molecules adhere preferentially to the silanized areas. This approach has also proven useful in patterning protein for cell adhesion studies. Finally, we describe the use of these stretched and aligned molecules of DNA as templates for the subsequent bottom-up construction of hetero-structures through hybridization

  4. Effects of stretching and warm-up routines on stability and balance during weight-lifting: a pilot investigation.

    Science.gov (United States)

    Adelsberger, Rolf; Tröster, Gerhard

    2014-12-20

    The efficacy of warm-up and stretching in weight-lifting remains unknown, especially for the weight-lifter's stability and balance during lifting. 13 subjects were randomly assigned a 10-minute stretching routine (SR) or a 10-minute warm-up routine (WR) and compared against 5 controls (no stretching or warm-up). Before and after the individually assigned routine, the participants' centre of pressure (CoP) was assessed using plantar-pressure sensors. The subjects were measured during 10 repetitions of air squat (no load, "AS"), front squat (FS; 20 kg/15 kg bar), overhead squat (OHS; m: 20 kg / f: 15 kg bar), and a deadlift lifting exercise ("DL"; 20 kg/15 kg bar). The impact on CoP dynamics of the warm-up and stretching routines were examined with repeated two-factor analysis of variances (ANOVA) of the mean and the coefficient of variance (CV, shown in %), as proxies for stability and balance. After stretching, the SR athletes shifted the mean CoP towards the toes (≈1 cm; p CoP towards the heels (≈1 cm; p CoP towards the heels (between 0.8 cm and 5.7 cm) compared to WR (≈1.9 cm towards the heels in FS, no significant change in OHS (≈1 mm) and DL (≈3 mm)). The controls did not show any change between pre- and post-datasets. After stretching, the CV decreased for the AS and OHS exercises (AS: 10.2% to 7.0%, OHS 9.8% to 7.8%), but increased after WR (AS: 7.1% to 10.1%) or did not change significantly (OHS). Both WR and SR resulted in increased CV values for FS and DL. No change of CV was observed in the controls. SR had a stronger impact on CoP during the assessed exercises than either WR or controls. A reduction in CV after SR exercises (AS, OHS) suggests a clear improvement in stability and balance during weight-lifting. The lack of a significant effect for complex movements (OHS) suggests only a limited effect of a 10-minute warm-up routine on CoP features. 10 minutes stretching might therefore be more efficient for improving stability than a general

  5. Muscle stretching exercises and resistance training in fibromyalgia: which is better? A three-arm randomized controlled trial.

    Science.gov (United States)

    Assumpção, Ana; Matsutani, Luciana A; Yuan, Susan L; Santo, Adriana S; Sauer, Juliana; Mango, Pamela; Marques, Amelia P

    2017-11-29

    Exercise therapy is an effective component of fibromyalgia (FM) treatment. However, it is important to know the effects and specificities of the different types of exercise: muscle stretching and resistance training. To verify and compare the effectiveness of muscle stretching exercise and resistance training for symptoms and quality of life in FM patients. Randomized controlled trial. Physical therapy service, FM outpatient clinic. Forty-four women with FM (79 screened). Patients were randomly allocated into a stretching group (n=14), resistance group (n=16), and control group (n=14). Pain was assessed using the visual analog scale, pain threshold using a Fischer dolorimeter, FM symptoms using the Fibromyalgia Impact Questionnaire (FIQ), and quality of life using the Medical Outcomes Study 36-item Short- Form Health Survey (SF-36). The three intervention groups continued with usual medical treatment. In addition, the stretching and resistance groups performed two different exercise programs twice a week for 12 weeks. After treatment, the stretching group showed the highest SF-36 physical functioning score (p=0.01) and the lowest bodily pain score (p=0.01). The resistance group had the lowest FIQ depression score (p=0.02). The control group had the highest score for FIQ morning tiredness and stiffness, and the lowest score for SF-36 vitality. In clinical analyses, the stretching group had significant improvement in quality of life for all SF-36 domains, and the resistance group had significant improvement in FM symptoms and in quality of life for SF-36 domains of physical functioning, vitality, social function, emotional role, and mental health. Muscle stretching exercise was the most effective modality in improving quality of life, especially with regard to physical functioning and pain, and resistance training was the most effective modality in reducing depression. The trial included a control group and two intervention groups, both of which received exercise

  6. Comparative Effectiveness of Straight Leg Raise and Slump Stretching in Subjects with Low Back Pain with Adverse Neural Tension

    Directory of Open Access Journals (Sweden)

    Neha Malik

    2016-03-01

    Full Text Available Background: Chronic low back pain is a common problem in the present time. It is commonly associated with altered mechanical tension in the peripheral nerves as tested by straight leg raising or slump tests. These maneuvers are used for treatment of such disorders. Both the straight leg raise and slump stretching techniques have been found to be beneficial in the treatment of low back pain with distal symptoms. A comparison of the two techniques will determine if one technique is better than the other. Also, it will add to the evidence for their effectiveness in managing symptoms in patients with low back pain. Objective: To evaluate the comparative effectiveness of straight leg raise and slump stretching on pain and range of passive straight leg raise in subjects with low back pain. Methods and measures: 50 patients with low back pain, satisfying the inclusion and exclusion criteria were randomly assigned to three groups. Group 1 was the straight leg raise group (n=15. Group 2 was the slump group (n=13. Group 3 was the control group (n=12. Baseline measurements of pain intensity as measured by the Numeric Pain Rating Scale (NPRS and range of passive straight leg raise (PSLR were taken. Group 1 received 6 sessions of straight leg raise stretching and lumbar stabilization exercises. Group 2 received 6 sessions of slump stretching and lumbar stabilization exercises. Group 3 received 6 sessions of lumbar stabilization exercises only. Statistical analysis: Paired t-test was used for within group analysis of NPRS and PSLR. ANOVA followed by post hoc analysis was employed for between group comparisons. Results: No significant difference was found in NPRS between straight leg raise and slump groups (p > 0.05 while they differed significantly in PSLR (p < 0.05. Both the groups showed significantly better results in PSLR when compared to the control group (P<0.05. Statistically significant improvements were found in all the 3 groups for both the outcome

  7. Short Term Effects of Neurodynamic Stretching and Static Stretching Techniques on Hamstring Muscle Flexibility in Healthy Male Subjects

    OpenAIRE

    Adel Rashad Ahmed; Ahmed Fathy Samhan

    2016-01-01

    Flexibility is a key component of rehabilitation and inadequate muscle extensibility remains a commonly accepted factor for musculoskeletal disorders. Studies on the most optimal technique for improving muscle flexibility are a widely debated. The aim of the study was to compare the effectiveness of neurodynamic and static stretching techniques on hamstring flexibility in healthy male subjects. This study was a randomized experimental trial; forty healthy male subjects with hamstr...

  8. Effects of Dynamic and Static Stretching Within General and Activity Specific Warm-Up Protocols

    OpenAIRE

    Samson, Michael; Button, Duane C.; Chaouachi, Anis; Behm, David G.

    2012-01-01

    The purpose of the study was to determine the effects of static and dynamic stretching protocols within general and activity specific warm-ups. Nine male and ten female subjects were tested under four warm-up conditions including a 1) general aerobic warm-up with static stretching, 2) general aerobic warm-up with dynamic stretching, 3) general and specific warm-up with static stretching and 4) general and specific warm-up with dynamic stretching. Following all conditions, subjects were tested...

  9. A simple constrained uniaxial tensile apparatus for in situ investigation of film stretching processing.

    Science.gov (United States)

    Meng, Lingpu; Li, Jing; Cui, Kunpeng; Chen, Xiaowei; Lin, Yuanfei; Xu, Jiali; Li, Liangbin

    2013-11-01

    A simple constrained uniaxial tensile apparatus was designed and constructed to obtain stress-strain curve during stretching and subsequent structural evolution of polymeric films. Stretch is carried out through two motor driven clamps in the machine direction and scissor-like clamps in the transverse direction keeping the sample width constant. The force information during film stretching process is recorded by a tension sensor and structural evolution can be obtained by in situ X-ray scattering technique. All parameters related to film stretching manufacturing, such as temperature, draw ratio, and stretching speed can be set independently, making the apparatus an effective method to explore the relationship between processing parameters and structure.

  10. Vascular surgical stretch injury leads to activation of P2X7 receptors and impaired endothelial function.

    Directory of Open Access Journals (Sweden)

    Padmini Komalavilas

    Full Text Available A viable vascular endothelial layer prevents vasomotor dysfunction, thrombosis, inflammation, and intimal hyperplasia. Injury to the endothelium occurs during harvest and "back table" preparation of human saphenous vein prior to implantation as an arterial bypass conduit. A subfailure overstretch model of rat aorta was used to show that subfailure stretch injury of vascular tissue leads to impaired endothelial-dependent relaxation. Stretch-induced impaired relaxation was mitigated by treatment with purinergic P2X7 receptor (P2X7R inhibitors, brilliant blue FCF (FCF and A740003, or apyrase, an enzyme that catalyzes the hydrolysis of ATP. Alternatively, treatment of rat aorta with exogenous ATP or 2'(3'-O-(4-Benzoyl benzoyl-ATP (BzATP also impaired endothelial-dependent relaxation. Treatment of human saphenous vein endothelial cells (HSVEC with exogenous ATP led to reduced nitric oxide production which was associated with increased phosphorylation of the stress activated protein kinase, p38 MAPK. ATP- stimulated p38 MAPK phosphorylation of HSVEC was inhibited by FCF and SB203580. Moreover, ATP inhibition of nitric oxide production in HSVEC was prevented by FCF, SB203580, L-arginine supplementation and arginase inhibition. Finally, L-arginine supplementation and arginase inhibition restored endothelial dependent relaxation after stretch injury of rat aorta. These results suggest that vascular stretch injury leads to ATP release, activation of P2X7R and p38 MAPK resulting in endothelial dysfunction due to arginase activation. Endothelial function can be restored in both ATP treated HSVEC and intact stretch injured rat aorta by P2X7 receptor inhibition with FCF or L-arginine supplementation, implicating straightforward therapeutic options for treatment of surgical vascular injury.

  11. Impact of the configuration of stretching and ocean-atmosphere coupling on tropical cyclone activity in the variable-resolution GCM ARPEGE

    Energy Technology Data Exchange (ETDEWEB)

    Daloz, Anne Sophie; Chauvin, Fabrice [CNRM-GAME, Groupe de Modelisation Grande Echelle et Climat, Toulouse Cedex 1 (France); Roux, Frank [Universite de Toulouse, Laboratoire d' Aerologie, Centre National de la Recherche Scientifique, Toulouse (France)

    2012-11-15

    This study starts by investigating the impact of the configuration of the variable-resolution atmospheric grid on tropical cyclone (TC) activity. The French atmospheric general circulation model ARPEGE, the grid of which is rotated and stretched over the North Atlantic basin, was used with prescribed sea surface temperatures. The study clearly shows that changing the position of the stretching pole strongly modifies the representation of TC activity over the North Atlantic basin. A pole in the centre of the North Atlantic basin provides the best representation of the TC activity for this region. In a second part, the variable-resolution climate model ARPEGE is coupled with the European oceanic global climate model NEMO in order to study the impact of ocean-atmosphere coupling on TC activity over the North Atlantic basin. Two pre-industrial runs, a coupled simulation and a simulation forced by the sea surface temperatures from the coupled one, are compared. The results show that the coupled simulation is more active in the Caribbean Sea and the Gulf of Mexico while the forced simulation is more active over eastern Florida and the eastern Atlantic. The difference in the distribution of TC activity is certainly linked with the location of TC genesis. In the forced simulation, tropical cyclogenesis is closer to the west African coast than in the coupled simulation. Moreover, the difference in TC activity over the eastern Atlantic seems to be related to two different mechanisms: the difference in African easterly wave activity over the west of Africa and the cooling produced, in the coupled simulation, by African easterly waves over the eastern Atlantic. Finally, the last part studies the impact of changing the frequency of ocean-atmosphere coupling on Atlantic TC activity. Increasing the frequency of coupling decreases the density of TC activity over the North Atlantic basin. However, it does not modify the spatial distribution of the TC activity. TC rainfalls are

  12. Impact of the configuration of stretching and ocean-atmosphere coupling on tropical cyclone activity in the variable-resolution GCM ARPEGE

    Science.gov (United States)

    Daloz, Anne Sophie; Chauvin, Fabrice; Roux, Frank

    2012-11-01

    This study starts by investigating the impact of the configuration of the variable-resolution atmospheric grid on tropical cyclone (TC) activity. The French atmospheric general circulation model ARPEGE, the grid of which is rotated and stretched over the North Atlantic basin, was used with prescribed sea surface temperatures. The study clearly shows that changing the position of the stretching pole strongly modifies the representation of TC activity over the North Atlantic basin. A pole in the centre of the North Atlantic basin provides the best representation of the TC activity for this region. In a second part, the variable-resolution climate model ARPEGE is coupled with the European oceanic global climate model NEMO in order to study the impact of ocean-atmosphere coupling on TC activity over the North Atlantic basin. Two pre-industrial runs, a coupled simulation and a simulation forced by the sea surface temperatures from the coupled one, are compared. The results show that the coupled simulation is more active in the Caribbean Sea and the Gulf of Mexico while the forced simulation is more active over eastern Florida and the eastern Atlantic. The difference in the distribution of TC activity is certainly linked with the location of TC genesis. In the forced simulation, tropical cyclogenesis is closer to the west African coast than in the coupled simulation. Moreover, the difference in TC activity over the eastern Atlantic seems to be related to two different mechanisms: the difference in African easterly wave activity over the west of Africa and the cooling produced, in the coupled simulation, by African easterly waves over the eastern Atlantic. Finally, the last part studies the impact of changing the frequency of ocean-atmosphere coupling on Atlantic TC activity. Increasing the frequency of coupling decreases the density of TC activity over the North Atlantic basin. However, it does not modify the spatial distribution of the TC activity. TC rainfalls are

  13. Nucleolar targeting of proteins by the tandem array of basic amino acid stretches identified in the RNA polymerase I-associated factor PAF49

    International Nuclear Information System (INIS)

    Ushijima, Ryujiro; Matsuyama, Toshifumi; Nagata, Izumi; Yamamoto, Kazuo

    2008-01-01

    There is accumulating evidence to indicate that the regulation of subnuclear compartmentalization plays important roles in cellular processes. The RNA polymerase I-associated factor PAF49 has been shown to accumulate in the nucleolus in growing cells, but disperse into the nucleoplasm in growth-arrested cells. Serial deletion analysis revealed that amino acids 199-338 were necessary for the nucleolar localization of PAF49. Combinatorial point mutation analysis indicated that the individual basic amino acid stretches (BS) within the central (BS1-4) and the C-terminal (BS5 and 6) regions may cooperatively confer the nucleolar localization of PAF49. Addition of the basic stretches in tandem to a heterologous protein, such as the interferon regulatory factor-3, translocated the tagged protein into the nucleolus, even in the presence of an intrinsic nuclear export sequence. Thus, tandem array of the basic amino acid stretches identified here functions as a dominant nucleolar targeting sequence

  14. PEMBERIAN INFRA RED, STRIPPING DAN STRETCHING TERHADAP NYERI TENSION HEADACHE DI PUSKESMAS TAPUS

    Directory of Open Access Journals (Sweden)

    Cici Apriza Yanti

    2018-03-01

    Full Text Available Prevalence of headache in Indonesia is very high. More than 90% of patients consult a doctor. The aim of research is to know the difference of pain after giving Infra Red, Stripping, and Stretching to the pain of tension headache. This research design is quasi experiment with pre and post test design. Population in this research is all patient of tension headache at Tapus Health Center. Sampling using accidental sampling with 10 samples. The data were collected using observation sheet of pain caused by tension headache. Data analysis was done by computerized using Wilcoxon test. The results showed that the mean intensity of pain before the 5.60 decreased to 4.78 after intervention and the mean intensity of tenderness before the 6.10 decreased to 5.27 after the intervention. The results of analysis showed that there was a difference in the intensity of pain (p = 0,005 and tenderness (p = 0,005.It can be concluded that therapy with Infra Red (IR, Stripping, and Stretching is effective to decreased pain intensity due to tension headache. For that it is expected to patients with pain complaints to tension headache to be always active and disciplined follow effective therapy in reducing the intensity of pain. Prevalensi sakit kepala di Indonesia sangatlah tinggi. Lebih dari 90% pasien yang berkonsultasi ke dokter. Penelitian ini bertujuan untuk mengetahui perbedaan nyeri tekan dan gerak setelah pemberian Infra Red, Stripping, dan Stretching terhadap nyeri pada kasus tension headache di Puskesmas Tapus Kabupaten Pasaman tahun 2016. Desain penelitian ini adalah quasi eksperiment dengan desain pre dan post test. Populasi pada penelitian adalah seluruh pasien tension headache di Puskesmas Tapus pada bulan Juni sampai Juli tahun 2016. Pengambilan sampel menggunakan teknik accidental sampling sehingga didapatkan sampel sebanyak 10 orang. Pengumpulan data penelitian menggunakan lembar observasi intensitas nyeri akibat tension headache. Analisis data

  15. Gene expression of stretch-activated channels and mechanoelectric feedback in the heart.

    Science.gov (United States)

    Kelly, D; Mackenzie, L; Hunter, P; Smaill, B; Saint, D A

    2006-07-01

    1. Mechanoelectric feedback (MEF) in the heart is the process by which mechanical forces on the myocardium can change its electrical properties. Mechanoelectric feedback has been demonstrated in many animal models, ranging from isolated cells, through isolated hearts to whole animals. In humans, MEF has been demonstrated directly in both the atria and the ventricles. It seems likely that MEF provides either the trigger or the substrate for some types of clinically important arrhythmias. 2. Mechanoelectric feedback may arise because of the presence of stretch-sensitive (or mechano-sensitive) ion channels in the cell membrane of the cardiac myocytes. Two types have been demonstrated: (i) a non-specific cation channel (stretch-activated channel (SAC); conductance of approximately 25 pS); and (ii) a potassium channel with a conductance of approximately 100 pS. The gene coding for the SAC has not yet been identified. The gene for the potassium channel is likely to be TREK, a member of the tandem pore potassium channel gene family. We have recorded stretch-sensitive potassium channels in rat isolated myocytes that have the properties of TREK channels expressed in heterologous systems. 3. It has been shown that TREK mRNA is expressed heterogeneously in the rat ventricular wall, with 17-fold more expression in endocardial compared with epicardial cells. This difference is reflected in the TREK currents recorded from endocardial and epicardial cells using whole-cell patch-clamp techniques, although the difference in current density was less pronounced (approximately threefold). Consistent with this, we show here that when the ventricle is stretched by inflation of an intraventricular balloon in a Langendorff perfused rat isolated heart, action potential shortening was more pronounced in the endocardium (30% shortening at 40 mmHg) compared with that in the epicardium (10% shortening at the same pressure). 4. Computer models of the mechanics of the (pig) heart show pronounced

  16. The effects of stabilization exercises using a sling and stretching on the range of motion and cervical alignment of straight neck patients.

    Science.gov (United States)

    Oh, Seung-Hyean; Yoo, Kyung-Tae

    2016-01-01

    [Purpose] The purpose of this study was to assess how stretching exercise training and sling exercise training for stabilization influences the cervical spine angles and cervical range of motion of straight neck patients. [Subjects and Methods] Twenty straight neck patients were selected as subjects and they were randomly divided into two groups, the stretching and sling stabilization exercise groups which 60 minutes of exercise three times a week for 6weeks. All the subjects in each of the two respective study groups received an X-ray and had their cervical range of motion measured, both before and after the exercise. [Results] When differences in the cervical spine angle between the pre- and the post-test were checked, it was found that only the stretching exercise group showed statistically significant decreases in the craniovertebral angle and the cranial rotation angle. When differences in the range of motion between pre- and post-test were checked, the sling stabilization exercise group showed a significant change in flexion, right rotation, left lateral bending, right lateral bending, and the stretching exercise group showed a significant change in left rotation, left lateral bending, and right lateral bending. [Conclusion] These results indicate that both types of exercises are effective at improving the cervical range of motion of straight neck patients, and that the stretching exercise was more effective than the sling stabilization exercise at improving cervical spine angles.

  17. Time course of the effects of static stretching on cycling economy.

    Science.gov (United States)

    Wolfe, Alyson E; Brown, Lee E; Coburn, Jared W; Kersey, Robert D; Bottaro, Martim

    2011-11-01

    Stretching has been implemented as part of the warm-up before physical events and widely thought to promote increased sport performance and decreased injury risk. However, recent research has concluded that static stretching before many exercises inhibits acute power, strength, and sprinting performance. There is little research examining the time course of these effects on moderate intensity cycling. The purpose of this study was to examine the time course of static stretching on cycling economy. The subjects consisted of 5 men and 5 women highly trained endurance cyclists. The first of 3 visits was baseline testing of their cycling VO2max. The second and third visits were either stretching or no stretching before a 30-minute stationary ride at 65% of their VO2max. The stretching condition consisted of four 30-second repetitions of 5 stretches with an average total stretching time of 16 minutes. VO2 demonstrated a significant condition by time interaction with the 5-minute time point being significantly less in the nonstretching condition (32.66 ± 5.35 ml·kg(-1)·min(-1)) than stretching (34.39 ± 5.39 ml·kg(-1)·min(-1)). No other time points were different. Our results demonstrate that static stretching yielded an acute increase in submaximal VO2; therefore, coaches and highly trained endurance cyclists should exclude static stretching immediately before moderate intensity cycling because it reduces acute cycling economy.

  18. Mechanical stretching for tissue engineering: two-dimensional and three-dimensional constructs.

    Science.gov (United States)

    Riehl, Brandon D; Park, Jae-Hong; Kwon, Il Keun; Lim, Jung Yul

    2012-08-01

    Mechanical cell stretching may be an attractive strategy for the tissue engineering of mechanically functional tissues. It has been demonstrated that cell growth and differentiation can be guided by cell stretch with minimal help from soluble factors and engineered tissues that are mechanically stretched in bioreactors may have superior organization, functionality, and strength compared with unstretched counterparts. This review explores recent studies on cell stretching in both two-dimensional (2D) and three-dimensional (3D) setups focusing on the applications of stretch stimulation as a tool for controlling cell orientation, growth, gene expression, lineage commitment, and differentiation and for achieving successful tissue engineering of mechanically functional tissues, including cardiac, muscle, vasculature, ligament, tendon, bone, and so on. Custom stretching devices and lab-specific mechanical bioreactors are described with a discussion on capabilities and limitations. While stretch mechanotransduction pathways have been examined using 2D stretch, studying such pathways in physiologically relevant 3D environments may be required to understand how cells direct tissue development under stretch. Cell stretch study using 3D milieus may also help to develop tissue-specific stretch regimens optimized with biochemical feedback, which once developed will provide optimal tissue engineering protocols.

  19. Possible Cause of Nonlinear Tension Rise in Activated Muscle Fiber during Stretching.

    Science.gov (United States)

    Kochubei, P V; Bershitsky, S Yu

    2016-11-01

    Tension in contracting muscle fiber under conditions of ramp stretching rapidly increases, but after reaching a critical stretch P c sharply decreases. To find out the cause of these changes in muscle fiber tension, we stopped stretching before and after reaching P c and left the fiber stretched for 50 msec. After rapid tension drop, the transient tension rise not accompanied by fiber stiffness increase was observed only in fibers heated to 25°C and stretched to P c . Under other experimental conditions, this growth was absent. We suppose that stretch of the fiber to P c induces transition of stereo-specifically attached myosin heads to pre-power stroke state and when the stretching is stopped, they make their step on actin and generate force. When the tension reaches P c , all stereospecifically attached myosin heads turn out to be non-stereospecifically, or weakly attached to actin, and are unable to make the force-generating step.

  20. Biaxial Stretch Improves Elastic Fiber Maturation, Collagen Arrangement, and Mechanical Properties in Engineered Arteries.

    Science.gov (United States)

    Huang, Angela H; Balestrini, Jenna L; Udelsman, Brooks V; Zhou, Kevin C; Zhao, Liping; Ferruzzi, Jacopo; Starcher, Barry C; Levene, Michael J; Humphrey, Jay D; Niklason, Laura E

    2016-06-01

    Tissue-engineered blood vessels (TEVs) are typically produced using the pulsatile, uniaxial circumferential stretch to mechanically condition and strengthen the arterial grafts. Despite improvements in the mechanical integrity of TEVs after uniaxial conditioning, these tissues fail to achieve critical properties of native arteries such as matrix content, collagen fiber orientation, and mechanical strength. As a result, uniaxially loaded TEVs can result in mechanical failure, thrombus, or stenosis on implantation. In planar tissue equivalents such as artificial skin, biaxial loading has been shown to improve matrix production and mechanical properties. To date however, multiaxial loading has not been examined as a means to improve mechanical and biochemical properties of TEVs during culture. Therefore, we developed a novel bioreactor that utilizes both circumferential and axial stretch that more closely simulates loading conditions in native arteries, and we examined the suture strength, matrix production, fiber orientation, and cell proliferation. After 3 months of biaxial loading, TEVs developed a formation of mature elastic fibers that consisted of elastin cores and microfibril sheaths. Furthermore, the distinctive features of collagen undulation and crimp in the biaxial TEVs were absent in both uniaxial and static TEVs. Relative to the uniaxially loaded TEVs, tissues that underwent biaxial loading remodeled and realigned collagen fibers toward a more physiologic, native-like organization. The biaxial TEVs also showed increased mechanical strength (suture retention load of 303 ± 14.53 g, with a wall thickness of 0.76 ± 0.028 mm) and increased compliance. The increase in compliance was due to combinatorial effects of mature elastic fibers, undulated collagen fibers, and collagen matrix orientation. In conclusion, biaxial stretching is a potential means to regenerate TEVs with improved matrix production, collagen organization, and mechanical

  1. Effect of frequency of static stretching on flexibility, hamstring tightness and electromyographic activity.

    Science.gov (United States)

    Marques, A P; Vasconcelos, A A P; Cabral, C M N; Sacco, I C N

    2009-10-01

    We compared the effect of the number of weekly repetitions of a static stretching program on the flexibility, hamstring tightness and electromyographic activity of the hamstring and of the triceps surae muscles. Thirty-one healthy subjects with hamstring tightness, defined as the inability to perform total knee extension, and shortened triceps surae, defined by a tibiotarsal angle wider than 90 degrees during trunk flexion, were divided into three groups: G1 performed the stretching exercises once a week; G2, three times a week, and G3, five times a week. The parameters were determined before and after the stretching program. Flexibility improved in all groups after intervention, from 7.65 +/- 10.38 to 3.67 +/- 12.08 in G1, from 10.73 +/- 12.07 to 0.77 +/- 10.45 in G2, and from 14.20 +/- 10.75 to 6.85 +/- 12.19 cm in G3 (P flexibility was higher in G2 than in G1 (P = 0.018), while G2 and G3 showed no significant difference (G1: 4 +/- 2.17, G2: 10 +/- 5.27; G3: 7.5 +/- 4.77 cm). Hamstring tightness improved in all groups, from 37.90 +/- 6.44 to 29 +/- 11.65 in G1, from 39.82 +/- 9.63 to 21.91 +/- 8.40 in G2, and from 37.20 +/- 6.63 to 26.10 +/- 5.72 degrees in G3 (P flexibility and range of motion compared to subjects exercising once a week, with results similar to those of subjects who exercised five times a week.

  2. Effect of different stretching volumes on functional capacity in elderly women

    Directory of Open Access Journals (Sweden)

    Luiza Herminia Gallo

    2013-01-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2013v15n1p103 The study aimed to analyze the effect of two different durations of stretching exercises, 90 or 180 seconds, on the functional capacity (FC of elderly women. Forty-three older women were assigned into three groups: inactive Control Group (CG, n. = 14, Training Group with three sets of 30 seconds (TG90, n. = 15 and Training Group with three sets of 60 seconds (TG180, n = 14. The TG90 and TG180 groups attended the university for 16 weeks, three times a week. The training protocol consisted of seven different static stretching exercises, performed in an active way. The CG attended the university only in periods of evaluations. Evaluations of the FC components and the Global Functional Fitness Index (GFFI, from the three groups, were both conducted before, and after 8 and 16 weeks of experiment, using a motor tests battery. The two-way ANOVA showed significant group x time interaction for the components flexibility, muscle strength and aerobic endurance, and for the GFFI values (p <0.05. The Scheffé post hoc test pointed difference between the two training groups and the CG, with no difference between TF90 and TG180. There was also improvement in the general classification of GFFI for the TG90 and TG180, which went from “fair” to “good”, while CG remained classified as “fair.” It was concluded that the two durations of stretching exercises were equally effective in improving flexibility, muscle strength, aerobic endurance and levels of FC in elderly women.

  3. Medial gastrocnemius muscle stiffness cannot explain the increased ankle joint range of motion following passive stretching in children with cerebral palsy.

    Science.gov (United States)

    Kalkman, Barbara M; Bar-On, Lynn; Cenni, Francesco; Maganaris, Constantinos N; Bass, Alfie; Holmes, Gill; Desloovere, Kaat; Barton, Gabor J; O'Brien, Thomas D

    2018-03-01

    What is the central question of this study? Can the increased range of motion seen acutely after stretching in children with cerebral palsy be explained by changes in the stiffness of the medial gastrocnemius fascicles? What is the main finding and its importance? We show, for the first time, that passive muscle and tendon properties are not changed acutely after a single bout of stretching in children with cerebral palsy and, therefore, do not contribute to the increase in range of motion. This contradicts common belief and what happens in healthy adults. Stretching is often used to increase or maintain the joint range of motion (ROM) in children with cerebral palsy (CP), but the effectiveness of these interventions is limited. Therefore, our aim was to determine the acute changes in muscle-tendon lengthening properties that contribute to increased ROM after a bout of stretching in children with CP. Eleven children with spastic CP [age 12.1 (3 SD) years, 5/6 hemiplegia/diplegia, 7/4 gross motor function classification system level I/II] participated. Each child received three sets of five × 20 s passive, manual static dorsiflexion stretches separated by 30 s rest, with 60 s rest between sets. Before and immediately after stretching, ultrasound was used to measure medial gastrocnemius fascicle lengthening continuously over the full ROM and an individual common ROM pre- to post-stretching. Simultaneously, three-dimensional motion of two marker clusters on the shank and the foot was captured to calculate ankle angle, and ankle joint torque was calculated from manually applied torques and forces on a six degrees-of-freedom load cell. After stretching, the ROM was increased [by 9.9 (12.0) deg, P = 0.005]. Over a ROM common to both pre- and post-measurements, there were no changes in fascicle lengthening or torque. The maximal ankle joint torque tolerated by the participants increased [by 2.9 (2.4) N m, P = 0.003], and at this highest passive torque the

  4. Intermittent But Not Continuous Static Stretching Improves Subsequent Vertical Jump Performance In Flexibility-Trained Athletes.

    Science.gov (United States)

    Bogdanis, Gregory C; Donti, Olyvia; Tsolakis, Charilaos; Smilios, Ilias; Bishop, David J

    2017-02-23

    This study examined changes in countermovement jump (CMJ) height after an intermittent or a continuous static stretching protocol of equal total duration. Sixteen male, elite-level gymnasts performed 90 s of intermittent (3 x 30 s with 30 s rest) or continuous stretching (90 s) of the quadriceps muscle. A single-leg stretching and jumping design was used, with the contra-lateral limb serving as a control. The same individuals performed both conditions with alternate legs in a randomized, counterbalanced order. One leg CMJ height was measured for the stretched and the control leg after warm-up, immediately after stretching, and at regular intervals for 10 min after stretching. Range of motion (ROM) of the hip and knee joints was measured before, after, and 10 min post-stretching. Compared to the control leg, intermittent stretching increased CMJ height by 8.1±2.0%, 4 min into recovery (+2.2±2.0 cm, 95%CI: 1.0-3.4 cm, p=0.001), while continuous stretching decreased CMJ height by 17.5±3.3% immediately after (-2.9±1.7 cm, 95%CI: -2.0 to -3.7 cm, p=0.001) and by 12.0±2.7% one min after stretching (-2.2±2.1 cm, 95%CI: -1.2 to -3.2 cm, p=0.001). The increases in hip (2.9 and 3.6, p=0.001. d=2.4) and knee joint ROM (5.1 and 6.1, p=0.001. d=0.85) after the intermittent and continuous stretching protocols were not different. The opposite effects of intermittent vs. continuous stretching on subsequent CMJ performance suggests that stretching mode is an important variable when examining the acute effects of static stretching on performance in flexibility-trained athletes.

  5. Stretched graphene tented by polycaprolactone and polypyrrole net–bracket for neurotransmitter detection

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhenzhen; Ying, Ye; Li, Li; Xu, Ting; Wu, Yiping; Guo, Xiaoyu; Wang, Feng; Shen, Haojie; Wen, Ying, E-mail: ying.wen@shnu.edu.cn; Yang, Haifeng, E-mail: Hfyang@shnu.edu.cn

    2017-02-28

    Highlights: • A new DA sensor is constructed with RGO and electrospun polymer fiber film. • RGO sheets can be mechanically stretched by the as-fabricated net-brackets. • The DA sensor shows highly catalytic activity toward the oxidation of dopamine. • The as-prepared sensor is used to detect DA in injection or urine. • The protocol to make sensors in large scale way has good reproducibility. - Abstract: A net-bracket built out from the core@shell structure of chemically oxidized polypyrrole (PPy) coated electrospun polycaprolactone (PCL) nanofibers, and the following surface modification of a thin layer of positively charged poly(dimethyl diallyl ammonium chloride) (PDDA) has been applied for stretching the reduced graphene oxide (RGO) sheets to some extent with the electrochemical deposition method. The as-formed RGO/PDDA/PCL@PPy nanocomposites were investigated by using scanning electron microscopy, transmission electron microscope, X-ray diffraction and Raman spectroscopy. The graphene tented by the net-bracket showed remarkable electrocatalytic properties in detecting the neurotransmitter dopamine (DA). Low detection limit of 0.34 μM (S/N = 3) with the wide linear detection range from 4 μM to 690 μM was obtained. The successful determination of DA in real urine samples and DA injection were achieved. Such attractive fabrication strategy can be extended to make other graphene sheet-based sensors.

  6. Effects of Stretching by P.N.F and Harmonic Techniques on Hamstring Flexibility

    Directory of Open Access Journals (Sweden)

    Hassan Shakeri

    2006-01-01

    Full Text Available Objective: Improving of muscle flexibility is an important issue in physiotherapy and sport sciences. There are many methods for increasing muscle length and decreasing muscle stiffness. In research findings, PNF method has been found to be better than static and ballistic methods. There is another method named Harmonic technique (introduced by E. Lederman 1997 that has been claimed to be more effective, but there is not enough documentation about this claim. Aim of this study was to compare effects of stretching by PNF and harmonic techniques on hamstring flexibility. Materials & Methods: This research is a RCT study in that 45 colledge students aged 18-35 years were arranged in three groups (Harmonic, P.N.F, and control. Subjects haven’t had any painful pathology in low-back and lower extremities for last six months. Subjects had limited hamstring length (20 degrees deficiency in Active-Knee-Extension test and hadn’t professional sport activities. Dependent variablies were muscle stiffness and hamstring length which popliteal angle in AKE test was its indirect index. In pilot study, reliability of measurement of these variables were approved. Then hamstring muscle of subjects in harmonic and PNF groups were stretched by harmonic and PNF methods for six weeks, 5 minute per day and 3d/wks, whereas control group hadn’t any exercise. Results: Findings of this study showed that in both used techniques, changes of hamstring length were significant (P=0.000, but in control group there wasn’t significant change. There wasn’t significant differences between changes of hamstring length in PNF and Harmonic groups. Only in harmonic group, muscle stiffness had significant changes (P<0.03. Conclusion: According to findings of this research, both harmonic and PNF methods equally increased length of hamstring, and harmonic technique can be used as an alternative stretching method for other techniques. Maybe harmonic technique is better than PNF

  7. Potential axillary nerve stretching during RSA implantation: an anatomical study.

    Science.gov (United States)

    Marion, Blandine; Leclère, Franck Marie; Casoli, Vincent; Paganini, Federico; Unglaub, Frank; Spies, Christian; Valenti, Philippe

    2014-09-01

    Clinical and subclinical neurological injury after reverse shoulder arthroplasty (RSA) may jeopardize functional outcomes due to the risk of irreversible damage to the axillary nerve. We proposed a simple anatomical study in order to assess the macroscopic effects on the axillary nerve when lowering the humerus as performed during RSA implantation. We also measured the effect on the axillary nerve of a lateralization of the humerus. Between 2011 and 2012, cadaveric dissections of 16 shoulder specimens from nine fresh human cadavers were performed in order to assess the effects on the axillary nerve after the lowering and lateralization of the humerus. We assessed the extent of stretching of the axillary nerve in four positions in the sagittal plane [lowering of the humerus: great tuberosity in contact with the acromion (position 1), in contact with the upper (position 2), middle (position 3) and lower rim of the glenoid (position 4)] and three positions in the frontal plane [lateralization of the humerus: humerus in contact with the glenoid (position 1), humerus lateralized 1 cm (position 2) and 2 cm (position 3)]. When the humerus was lowered, clear macroscopical changes appeared below the middle of the glenoid (the highest level of tension). As regards the lateralization of the humerus, macroscopic study and measurements confirm the absence of stretching of the nerve in those positions. Lowering of the humerus below the equator of the glenoid changes the course and tension of the axillary nerve and may lead to stretching and irreversible damage, compromising the function of the deltoid. Improvements in the design of the implants and modification of the positioning of the glenosphere to avoid notching and to increase mobility must take into account the anatomical changes induced by the prosthesis and its impact on the brachial plexus. Level of Evidence and study type Level IV.

  8. Resistance training vs. static stretching: effects on flexibility and strength.

    Science.gov (United States)

    Morton, Sam K; Whitehead, James R; Brinkert, Ronald H; Caine, Dennis J

    2011-12-01

    Morton, SK, Whitehead, JR, Brinkert, RH, and Caine, DJ. Resistance training vs. static stretching: Effects on flexibility and strength. J Strength Cond Res 25(12): 3391-3398, 2011-The purpose of this study was to determine how full-range resistance training (RT) affected flexibility and strength compared to static stretching (SS) of the same muscle-joint complexes in untrained adults. Volunteers (n = 25) were randomized to an RT or SS training group. A group of inactive volunteers (n = 12) served as a convenience control group (CON). After pretesting hamstring extension, hip flexion and extension, shoulder extension flexibility, and peak torque of quadriceps and hamstring muscles, subjects completed 5-week SS or RT treatments in which the aim was to stretch or to strength train the same muscle-joint complexes over similar movements and ranges. Posttests of flexibility and strength were then conducted. There was no difference in hamstring flexibility, hip flexion, and hip extension improvement between RT and SS, but both were superior to CON values. There were no differences between groups on shoulder extension flexibility. The RT group was superior to the CON in knee extension peak torque, but there were no differences between groups on knee flexion peak torque. The results of this preliminary study suggest that carefully constructed full-range RT regimens can improve flexibility as well as the typical SS regimens employed in conditioning programs. Because of the potential practical significance of these results to strength and conditioning programs, further studies using true experimental designs, larger sample sizes, and longer training durations should be conducted with the aim of confirming or disproving these results.

  9. Ultrafast quantitative time-stretch imaging flow cytometry of phytoplankton

    Science.gov (United States)

    Lai, Queenie T. K.; Lau, Andy K. S.; Tang, Anson H. L.; Wong, Kenneth K. Y.; Tsia, Kevin K.

    2016-03-01

    Comprehensive quantification of phytoplankton abundance, sizes and other parameters, e.g. biomasses, has been an important, yet daunting task in aquatic sciences and biofuel research. It is primarily because of the lack of effective tool to image and thus accurately profile individual microalgae in a large population. The phytoplankton species are highly diversified and heterogeneous in terms of their sizes and the richness in morphological complexity. This fact makes time-stretch imaging, a new ultrafast real-time optical imaging technology, particularly suitable for ultralarge-scale taxonomic classification of phytoplankton together with quantitative image recognition and analysis. We here demonstrate quantitative imaging flow cytometry of single phytoplankton based on quantitative asymmetric-detection time-stretch optical microscopy (Q-ATOM) - a new time-stretch imaging modality for label-free quantitative phase imaging without interferometric implementations. Sharing the similar concept of Schlieren imaging, Q-ATOM accesses multiple phase-gradient contrasts of each single phytoplankton, from which the quantitative phase profile is computed. We employ such system to capture, at an imaging line-scan rate of 11.6 MHz, high-resolution images of two phytoplankton populations (scenedesmus and chlamydomonas) in ultrafast microfluidic flow (3 m/s). We further perform quantitative taxonomic screening analysis enabled by this technique. More importantly, the system can also generate quantitative phase images of single phytoplankton. This is especially useful for label-free quantification of biomasses (e.g. lipid droplets) of the particular species of interest - an important task adopted in biofuel applications. Combining machine learning for automated classification, Q-ATOM could be an attractive platform for continuous and real-time ultralarge-scale single-phytoplankton analysis.

  10. The long string at the stretched horizon and the entropy of large non-extremal black holes

    International Nuclear Information System (INIS)

    Mertens, Thomas G.; Verschelde, Henri; Zakharov, Valentin I.

    2016-01-01

    We discuss how long strings can arise at the stretched horizon and how they can account for the Bekenstein-Hawking entropy. We use the thermal scalar field theory to derive the asymptotic density of states and corresponding stress tensor of a microcanonical long string gas in Rindler space. We show that the equality of the Hagedorn and Hawking temperatures gives rise to the tree-level entropy of large black holes in accordance with the Bekenstein-Hawking-Wald formula.

  11. The long string at the stretched horizon and the entropy of large non-extremal black holes

    Energy Technology Data Exchange (ETDEWEB)

    Mertens, Thomas G. [Joseph Henry Laboratories, Princeton University,Washington Road, Princeton, NJ 08544 (United States); Ghent University, Department of Physics and Astronomy,Krijgslaan, 281-S9, 9000 Gent (Belgium); Verschelde, Henri [Ghent University, Department of Physics and Astronomy,Krijgslaan, 281-S9, 9000 Gent (Belgium); Zakharov, Valentin I. [ITEP,B. Cheremushkinskaya 25, Moscow 117218 (Russian Federation); Moscow Institute Phys. & Technol.,Dolgoprudny, Moscow Region 141700 (Russian Federation); School of Biomedicine, Far Eastern Federal University,Sukhanova str 8, Vladivostok 690950 (Russian Federation)

    2016-02-04

    We discuss how long strings can arise at the stretched horizon and how they can account for the Bekenstein-Hawking entropy. We use the thermal scalar field theory to derive the asymptotic density of states and corresponding stress tensor of a microcanonical long string gas in Rindler space. We show that the equality of the Hagedorn and Hawking temperatures gives rise to the tree-level entropy of large black holes in accordance with the Bekenstein-Hawking-Wald formula.

  12. Heat and mass transfer of a second grade magnetohydrodynamic fluid over a convectively heated stretching sheet

    Directory of Open Access Journals (Sweden)

    Kalidas Das

    2016-10-01

    Full Text Available The present work is concerned with heat and mass transfer of an electrically conducting second grade MHD fluid past a semi-infinite stretching sheet with convective surface heat flux. The analysis accounts for thermophoresis and thermal radiation. A similarity transformations is used to reduce the governing equations into a dimensionless form. The local similarity equations are derived and solved using Nachtsheim-Swigert shooting iteration technique together with Runge–Kutta sixth order integration scheme. Results for various flow characteristics are presented through graphs and tables delineating the effect of various parameters characterizing the flow. Our analysis explores that the rate of heat transfer enhances with increasing the values of the surface convection parameter. Also the fluid velocity and temperature in the boundary layer region rise significantly for increasing the values of thermal radiation parameter.

  13. Labrets: Piercing and Stretching on the Northwest Coast and in Amazonia

    Directory of Open Access Journals (Sweden)

    Jenny Reddish

    2014-05-01

    Full Text Available This article examines the practice of piercing and stretching the lip in order to accommodate a labret in two regions: the North American Northwest Coast (with historical examples from Tlingit and Haida groups and lowland South America (utilizing ethnographic writings on Suya and Kayapo communities. Drawing on the recent ‘sensorial turn’ within anthropology, I suggest an approach which goes beyond considerations of the symbolism of body ornaments and analyses how the infliction of pain they involve can be manipulated to serve social ends at a local level. Also discussed is the use of labrets within global ‘mediascapes’ (Appadurai 1996 by Kayapo and Northwest Coast groups in the context of self-representation and the politicization of ‘culture’ (Wright 1998.

  14. A wearable skin stretch haptic feedback device: Towards improving balance control in lower limb amputees.

    Science.gov (United States)

    Husman, M A B; Maqbool, H F; Awad, M I; Abouhossein, A; Dehghani-Sanij, A A

    2016-08-01

    Haptic feedback to lower limb amputees is essential to maximize the functionality of a prosthetic device by providing information to the user about the interaction with the environment and the position of the prostheses in space. Severed sensory pathway and the absence of connection between the prosthesis and the Central Nervous System (CNS) after lower limb amputation reduces balance control, increases visual dependency and increases risk of falls among amputees. This work describes the design of a wearable haptic feedback device for lower limb amputees using lateral skin-stretch modality intended to serve as a feedback cue during ambulation. A feedback scheme was proposed based on gait event detection for possible real-time postural adjustment. Preliminary perceptual test with healthy subjects in static condition was carried out and the results indicated over 98% accuracy in determining stimuli location around the upper leg region, suggesting good perceptibility of the delivered stimuli.

  15. Computation of nuclear reactor parameters using a stretch Kalman filtering

    International Nuclear Information System (INIS)

    Zwingelstein, G.; Poujol, A.

    1976-01-01

    A method of nonlinear stochastic filtering, the stretched Karman filter, is used for the estimation of two basic parameters involved in the control of nuclear reactor start-up. The corresponding algorithm is stored in a small Multi-8 computer and tested with data recorded for the Ulysse reactor (I.N.S.T.N.). The various practical problems involved in using the algorithm are examined: filtering initialization, influence of the model... The quality and time saving obtained in the computation make it possible for a real time operation, the computer being connected with the reactor [fr

  16. Boundary layer flow of nanofluid over an exponentially stretching surface

    Science.gov (United States)

    Nadeem, Sohail; Lee, Changhoon

    2012-01-01

    The steady boundary layer flow of nanofluid over an exponential stretching surface is investigated analytically. The transport equations include the effects of Brownian motion parameter and thermophoresis parameter. The highly nonlinear coupled partial differential equations are simplified with the help of suitable similarity transformations. The reduced equations are then solved analytically with the help of homotopy analysis method (HAM). The convergence of HAM solutions are obtained by plotting h-curve. The expressions for velocity, temperature and nanoparticle volume fraction are computed for some values of the parameters namely, suction injection parameter α, Lewis number Le, the Brownian motion parameter Nb and thermophoresis parameter Nt.

  17. Boundary layer flow of nanofluid over an exponentially stretching surface.

    Science.gov (United States)

    Nadeem, Sohail; Lee, Changhoon

    2012-01-30

    The steady boundary layer flow of nanofluid over an exponential stretching surface is investigated analytically. The transport equations include the effects of Brownian motion parameter and thermophoresis parameter. The highly nonlinear coupled partial differential equations are simplified with the help of suitable similarity transformations. The reduced equations are then solved analytically with the help of homotopy analysis method (HAM). The convergence of HAM solutions are obtained by plotting h-curve. The expressions for velocity, temperature and nanoparticle volume fraction are computed for some values of the parameters namely, suction injection parameter α, Lewis number Le, the Brownian motion parameter Nb and thermophoresis parameter Nt.

  18. Duration of static stretching influences muscle force production in hamstring muscles.

    Science.gov (United States)

    Ogura, Yuji; Miyahara, Yutetsu; Naito, Hisashi; Katamoto, Shizuo; Aoki, Junichiro

    2007-08-01

    The purpose of the present study was to investigate whether duration of static stretching could affect the maximal voluntary contraction (MVC). Volunteer male subjects (n = 10) underwent 2 different durations of static stretching of their hamstring muscles in the dominant leg: 30 and 60 seconds. No static stretching condition was used as a control condition. Before and after each stretching trial, hamstring flexibility was measured by a sit and reach test. MVC was then measured using the maximal effort of knee flexion. The hamstring flexibility was significantly increased by 30 and 60 seconds of static stretching (control: 0.5 +/- 1.1 cm; 30 seconds: 2.1 +/- 1.8 cm; 60 seconds: 3.0 +/- 1.6 cm); however, there was no significant difference between 30 and 60 seconds of static stretching conditions. The MVC was significantly lowered with 60 seconds of static stretching compared to the control and 30 seconds of the stretching conditions (control: 287.6 +/- 24.0 N; 30 seconds: 281.8 +/- 24.2 N; 60 seconds: 262.4 +/- 36.2 N). However, there was no significant difference between control and 30 seconds of static stretching conditions. Therefore, it was concluded that the short duration (30 seconds) of static stretching did not have a negative effect on the muscle force production.

  19. Acute effects of static, dynamic, and proprioceptive neuromuscular facilitation stretching on muscle power in women.

    Science.gov (United States)

    Manoel, Mateus E; Harris-Love, Michael O; Danoff, Jerome V; Miller, Todd A

    2008-09-01

    The purpose of this study was to investigate the acute effects of 3 types of stretching-static, dynamic, and proprioceptive neuromuscular facilitation (PNF)-on peak muscle power output in women. Concentric knee extension power was measured isokinetically at 60 degrees x s(-1) and 180 degrees x s(-1) in 12 healthy and recreationally active women (mean age +/- SD, 24 +/- 3.3 years). Testing occurred before and after each of 3 different stretching protocols and a control condition in which no stretching was performed. During 4 separate laboratory visits, each subject performed 5 minutes of stationary cycling at 50 W before performing the control condition, static stretching protocol, dynamic stretching protocol, or PNF protocol. Three submaximal warm-up trials preceded 3 maximal knee extensions at each testing velocity. A 2-minute rest was allowed between testing at each velocity. The results of the statistical analysis indicated that none of the stretching protocols caused a decrease in knee extension power. Dynamic stretching produced percentage increases (8.9% at 60 degrees x s(-1) and 6.3% at 180 degrees x s(-1)) in peak knee extension power at both testing velocities that were greater than changes in power after static and PNF stretching. The findings suggest that dynamic stretching may increase acute muscular power to a greater degree than static and PNF stretching. These findings may have important implications for athletes who participate in events that rely on a high level of muscular power.

  20. The effect of static, ballistic, and proprioceptive neuromuscular facilitation stretching on vertical jump performance.

    Science.gov (United States)

    Bradley, Paul S; Olsen, Peter D; Portas, Matthew D

    2007-02-01

    The purpose of this study was to compare the acute effects of different modes of stretching on vertical jump performance. Eighteen male university students (age, 24.3 +/- 3.2 years; height, 181.5 +/- 11.4 cm; body mass, 78.1 +/- 6.4 kg; mean +/- SD) completed 4 different conditions in a randomized order, on different days, interspersed by a minimum of 72 hours of rest. Each session consisted of a standard 5-minute cycle warm-up, accompanied by one of the subsequent conditions: (a) control, (b) 10-minute static stretching, (c) 10-minute ballistic stretching, or (d) 10-minute proprioceptive neuromuscular facilitation (PNF) stretching. The subjects performed 3 trials of static and countermovement jumps prior to stretching and poststretching at 5, 15, 30, 45, and 60 minutes. Vertical jump height decreased after static and PNF stretching (4.0% and 5.1%, p 0.05). However, jumping performance had fully recovered 15 minutes after all stretching conditions. In conclusion, vertical jump performance is diminished for 15 minutes if performed after static or PNF stretching, whereas ballistic stretching has little effect on jumping performance. Consequently, PNF or static stretching should not be performed immediately prior to an explosive athletic movement.

  1. Static stretching does not alter pre and post-landing muscle activation

    Directory of Open Access Journals (Sweden)

    Moss Wesley R

    2011-05-01

    Full Text Available Abstract Background Static stretching may result in various strength and power deficiencies. Prior research has not determined, however, if static stretching causes a change in muscle activation during a functional task requiring dynamic stability. The purpose of this study was to determine if static stretching has an effect on mean pre and postlanding muscle (vastus medialis VM, vastus lateralis VL, medial hamstring MH, and biceps femoris BF activity. Methods 26 healthy, physically active subjects were recruited, from which 13 completed a 14-day static stretching regimen for the quadriceps and hamstrings. Using the data from the force plate and EMG readings, a mean of EMG amplitude was calculated for 150 msec before and after landing. Each trial was normalized to an isometric reference position. Means were calculated for the VM, VL, MH, and BF from 5 trials in each session. Measures were collected pre, immediately following the 1st stretching session, and following 2 weeks of stretching. Results A 14-day static stretching regimen resulted in no significant differences in pre or postlanding mean EMG amplitude during a drop landing either acutely or over a 14-day period. Conclusions Static stretching, done acutely or over a 14-day period does not result in measurable differences of mean EMG amplitude during a drop landing. Static stretching may not impede dynamic stability of joints about which stretched muscles cross.

  2. Acute effect of a ballistic and a static stretching exercise bout on flexibility and maximal strength.

    Science.gov (United States)

    Bacurau, Reury Frank Pereira; Monteiro, Gizele Assis; Ugrinowitsch, Carlos; Tricoli, Valmor; Cabral, Leonardo Ferreira; Aoki, Marcelo Saldanha

    2009-01-01

    Different stretching techniques have been used during warm-up routines. However, these routines may decrease force production. The purpose of this study was to compare the acute effect of a ballistic and a static stretching protocol on lower-limb maximal strength. Fourteen physically active women (169.3 +/- 8.2 cm; 64.9 +/- 5.9 kg; 23.1 +/- 3.6 years) performed three experimental sessions: a control session (estimation of 45 degrees leg press one-repetition maximum [1RM]), a ballistic session (20 minutes of ballistic stretch and 45 degrees leg press 1RM), and a static session (20 minutes of static stretch and 45 degrees leg press 1RM). Maximal strength decreased after static stretching (213.2 +/- 36.1 to 184.6 +/- 28.9 kg), but it was unaffected by ballistic stretching (208.4 +/- 34.8 kg). In addition, static stretching exercises produce a greater acute improvement in flexibility compared with ballistic stretching exercises. Consequently, static stretching may not be recommended before athletic events or physical activities that require high levels of force. On the other hand, ballistic stretching could be more appropriate because it seems less likely to decrease maximal strength.

  3. Touch Locating and Stretch Sensing Studies of Conductive Hydrogels with Applications to Soft Robots

    Directory of Open Access Journals (Sweden)

    Yanmin Zhou

    2018-02-01

    Full Text Available Soft robots possess great potential in environmental adaptations, while their environmental sensing abilities are critical. Conductive hydrogels have been suggested to possess sensing abilities. However, their application in soft robots is lacking. In this work, we fabricated a soft and stretchable gel material, introduced its sensing mechanisms, and developed a measurement setup. Both experimental and simulation studies indicate strong nonlinearity of touch locating on a square touch panel with Cartesian coordinates. To simplify the touch locating, we proposed a touch locating system based on round touch panels with polar coordinates. Mathematical calculations and finite element method (FEM simulations showed that in this system the locating of a touch point was only determined by its polar radius. This was verified by experimental studies. As a resistor, a gel strip’s resistance increases with stretching. To demonstrate their applications on soft robots, a 3D printed three-fingered soft gripper was employed with gel strips attached. During finger bending for rod grasping, the resistances of the gel strips increased, indicating stretching of the soft material. Furthermore, the strain and stress of a gel strip increased with a decrease of the rod diameter. These studies advance the application of conductive hydrogels on soft robots.

  4. Boundary layer flow and heat transfer to Carreau fluid over a nonlinear stretching sheet

    Directory of Open Access Journals (Sweden)

    Masood Khan

    2015-10-01

    Full Text Available This article studies the Carreau viscosity model (which is a generalized Newtonian model and then use it to obtain a formulation for the boundary layer equations of the Carreau fluid. The boundary layer flow and heat transfer to a Carreau model over a nonlinear stretching surface is discussed. The Carreau model, adequate for many non-Newtonian fluids, is used to characterize the behavior of the fluids having shear thinning properties and fluids with shear thickening properties for numerical values of the power law exponent n. The modeled boundary layer conservation equations are converted to non-linear coupled ordinary differential equations by a suitable transformation. Numerical solution of the resulting equations are obtained by using the Runge-Kutta Fehlberg method along with shooting technique. This analysis reveals many important physical aspects of flow and heat transfer. Computations are performed for different values of the stretching parameter (m, the Weissenberg number (We and the Prandtl number (Pr. The obtained results show that for shear thinning fluid the fluid velocity is depressed by the Weissenberg number while opposite behavior for the shear thickening fluid is observed. A comparison with previously published data in limiting cases is performed and they are in excellent agreement.

  5. Fish assemblages in stream stretches occupied by cattail (Typhaceae, Angiospermae stands in Southeast Brazil

    Directory of Open Access Journals (Sweden)

    Fabíola Carla da Rocha

    Full Text Available Macrophytes are a major component of lentic and lotic aquatic ecosystems. As consequences of environmental degradation, species of cattail (genus Typha may become dominant along streams. The purpose of this study was to investigate the structure and feeding of fish assemblages in stream stretches under influence of Typha sp., also addressing the influences of temporal variation on composition, abundance, biomass, diversity, species richness, and feeding of fish. Six streams (labelled S1-S6 in the upper rio Turvo basin, southeast Brazil, with dense stands of Typha sp. in the instream and riparian habitat, were studied in six campaigns during three central months in both of the dry and wet periods, by using a standardized collection effort. Thirty-seven fish species were registered, totaling 4,228 individuals and 3.9 kg of biomass. Abundance, biomass, diversity, and species richness was higher in the wet period, but only the temporal variation in the species richness revealed to be statistically significant. Cluster analyses with composition and abundance showed little temporal similarity, but indicated two groups of streams (S1-S2-S5 and S3-S4-S6, that were corroborated along the axis 1 of the ordination analysis. Resident species was represented by six species, most of them considered tolerant and generalists. Chironomidae aquatic larvae and detritus were the most important items in the fish diet. These results suggest that the fish populations are opportunistic in exploring stream stretches occupied by cattail.

  6. Active and passive controls of Jeffrey nanofluid flow over a nonlinear stretching surface

    Science.gov (United States)

    Hayat, Tasawar; Aziz, Arsalan; Muhammad, Taseer; Alsaedi, Ahmed

    This communication explores magnetohydrodynamic (MHD) boundary-layer flow of Jeffrey nanofluid over a nonlinear stretching surface with active and passive controls of nanoparticles. A nonlinear stretching surface generates the flow. Effects of thermophoresis and Brownian diffusion are considered. Jeffrey fluid is electrically conducted subject to non-uniform magnetic field. Low magnetic Reynolds number and boundary-layer approximations have been considered in mathematical modelling. The phenomena of impulsing the particles away from the surface in combination with non-zero mass flux condition is known as the condition of zero mass flux. Convergent series solutions for the nonlinear governing system are established through optimal homotopy analysis method (OHAM). Graphs have been sketched in order to analyze that how the temperature and concentration distributions are affected by distinct physical flow parameters. Skin friction coefficient and local Nusselt and Sherwood numbers are also computed and analyzed. Our findings show that the temperature and concentration distributions are increasing functions of Hartman number and thermophoresis parameter.

  7. Theoretical modelling of physiologically stretched vessel in magnetisable stent assisted magnetic drug targeting application

    International Nuclear Information System (INIS)

    Mardinoglu, Adil; Cregg, P.J.; Murphy, Kieran; Curtin, Maurice; Prina-Mello, Adriele

    2011-01-01

    The magnetisable stent assisted magnetic targeted drug delivery system in a physiologically stretched vessel is considered theoretically. The changes in the mechanical behaviour of the vessel are analysed under the influence of mechanical forces generated by blood pressure. In this 2D mathematical model a ferromagnetic, coiled wire stent is implanted to aid collection of magnetic drug carrier particles in an elastic tube, which has similar mechanical properties to the blood vessel. A cyclic mechanical force is applied to the elastic tube to mimic the mechanical stress and strain of both the stent and vessel while in the body due to pulsatile blood circulation. The magnetic dipole-dipole and hydrodynamic interactions for multiple particles are included and agglomeration of particles is also modelled. The resulting collection efficiency of the mathematical model shows that the system performance can decrease by as much as 10% due to the effects of the pulsatile blood circulation. - Research highlights: →Theoretical modelling of magnetic drug targeting on a physiologically stretched stent-vessel system. →Cyclic mechanical force applied to mimic the mechanical stress and strain of both stent and vessel. →The magnetic dipole-dipole and hydrodynamic interactions for multiple particles is modelled. →Collection efficiency of the mathematical model is calculated for different physiological blood flow and magnetic field strength.

  8. Effect of homogenous-heterogeneous reactions on MHD Prandtl fluid flow over a stretching sheet

    Directory of Open Access Journals (Sweden)

    Imad Khan

    Full Text Available An analysis is performed to explore the effects of homogenous-heterogeneous reactions on two-dimensional flow of Prandtl fluid over a stretching sheet. In present analysis, we used the developed model of homogeneous–heterogeneous reactions in boundary layer flow. The mathematical configuration of presented flow phenomenon yields the nonlinear partial differential equations. Using scaling transformations, the governing partial differential equations (momentum equation and homogenous-heterogeneous reactions equations are transformed into non-linear ordinary differential equations (ODE’s. Then, resulting non-linear ODE’s are solved by computational scheme known as shooting method. The quantitative and qualitative manners of concerned physical quantities (velocity, concentration and drag force coefficient are examined under prescribed physical constrained through figures and tables. It is observed that velocity profile enhances verses fluid parameters α and β while Hartmann number reduced it. The homogeneous and heterogeneous reactions parameters have reverse effects on concentration profile. Concentration profile shows retarding behavior for large values of Schmidt number. Skin fraction coefficient enhances with increment in Hartmann number H and fluid parameter α. Keywords: Prandtl fluid, Homogeneous-heterogeneous reactions, Stretching sheet, MHD

  9. Touch Locating and Stretch Sensing Studies of Conductive Hydrogels with Applications to Soft Robots.

    Science.gov (United States)

    Zhou, Yanmin; He, Bin; Yan, Zhe; Shang, Yinghui; Wang, Qigang; Wang, Zhipeng

    2018-02-13

    Soft robots possess great potential in environmental adaptations, while their environmental sensing abilities are critical. Conductive hydrogels have been suggested to possess sensing abilities. However, their application in soft robots is lacking. In this work, we fabricated a soft and stretchable gel material, introduced its sensing mechanisms, and developed a measurement setup. Both experimental and simulation studies indicate strong nonlinearity of touch locating on a square touch panel with Cartesian coordinates. To simplify the touch locating, we proposed a touch locating system based on round touch panels with polar coordinates. Mathematical calculations and finite element method (FEM) simulations showed that in this system the locating of a touch point was only determined by its polar radius. This was verified by experimental studies. As a resistor, a gel strip's resistance increases with stretching. To demonstrate their applications on soft robots, a 3D printed three-fingered soft gripper was employed with gel strips attached. During finger bending for rod grasping, the resistances of the gel strips increased, indicating stretching of the soft material. Furthermore, the strain and stress of a gel strip increased with a decrease of the rod diameter. These studies advance the application of conductive hydrogels on soft robots.

  10. Stretched exponential relaxation processes in hydrogenated amorphous and polymorphous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Morigaki, Kazuo [Department of Electrical and Digital-System Engineering, Hiroshima Institute of Technology, Miyake, Saeki-ku, Hiroshima 731-5193 (Japan); Hikita, Harumi [Physics Laboratory, Meikai University, Urayasu, Chiba 279-8550 (Japan)

    2011-09-15

    Stretched exponential relaxation has been observed in various phenomena of hydrogenated amorphous silicon (a-Si:H) and hydrogenated polymorphous silicon (pm-Si:H). As an example, we take light-induced defect creation in a-Si:H and pm-Si:H, in which defect-creation process and defect-annihilation process via hydrogen movement play important roles. We have performed the Monte Carlo simulation for hydrogen movement. Hydrogen movement exhibits anomalous diffusion. In our model of light-induced defect creation in a-Si:H, a pair of two types of dangling bonds, i.e., a normal dangling bond and a hydrogen-related dangling bond, that is a dangling bond having hydrogen in the nearby site, are created under illumination, and hydrogen dissociated from the hydrogen-related dangling bond terminates a normal dangling bond via hydrogen movement. The amorphous network reflects on the dispersive parameter of the stretched exponential function in the light-induced defect creation. We discuss this issue, taking into account the difference in the amorphous network between a-Si:H and pm-Si:H (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Tangential stretching rate (TSR) analysis of non premixed reactive flows

    KAUST Repository

    Valorani, Mauro

    2016-10-16

    We discuss how the Tangential stretching rate (TSR) analysis, originally developed and tested for spatially homogeneous systems (batch reactors), is extended to spatially non homogeneous systems. To illustrate the effectiveness of the TSR diagnostics, we study the ignition transient in a non premixed, reaction–diffusion model in the mixture fraction space, whose dependent variables are temperature and mixture composition. The reactive mixture considered is syngas/air. A detailed H2/CO mechanism with 12 species and 33 chemical reactions is employed. We will discuss two cases, one involving only kinetics as a model of front propagation purely driven by spontaneous ignition, the other as a model of deflagration wave involving kinetics/diffusion coupling. We explore different aspects of the system dynamics such as the relative role of diffusion and kinetics, the evolution of kinetic eigenvalues, and of the tangential stretching rates computed by accounting for the combined action of diffusion and kinetics as well for kinetics only. We propose criteria based on the TSR concept which allow to identify the most ignitable conditions and to discriminate between spontaneous ignition and deflagration front.

  12. Analysis of a Stretched Derivative Aircraft with Open Rotor Propulsion

    Science.gov (United States)

    Berton, Jeffrey J.; Hendricks, Eric S.; Haller, William J.; Guynn, Mark D.

    2015-01-01

    Research into advanced, high-speed civil turboprops received significant attention during the 1970s and 1980s when fuel efficiency was the driving focus of U.S. aeronautical research. But when fuel prices declined sharply there was no longer sufficient motivation to continue maturing the technology. Recent volatility in fuel prices and increasing concern for aviation's environmental impact, however, have renewed interest in unducted, open rotor propulsion and revived research by NASA and a number of engine manufacturers. Recently, NASA and General Electric have teamed to conduct several investigations into the performance and noise of an advanced, single-aisle transport with open rotor propulsion. The results of these initial studies indicate open rotor engines have the potential to provide significant reduction in fuel consumption compared to aircraft using turbofan engines with equivalent core technology. In addition, noise analysis of the concept indicates that an open rotor aircraft in the single-aisle transport class would be able to meet current noise regulations with margin. The behavior of derivative open rotor transports is of interest. Heavier, "stretched" derivative aircraft tend to be noisier than their lighter relatives. Of particular importance to the business case for the concept is how the noise margin changes relative to regulatory limits within a family of similar open rotor aircraft. The subject of this report is a performance and noise assessment of a notional, heavier, stretched derivative airplane equipped with throttle-push variants of NASA's initial open rotor engine design.

  13. Harmonics analysis of the photonic time stretch system.

    Science.gov (United States)

    Mei, Yuan; Xu, Boyu; Chi, Hao; Jin, Tao; Zheng, Shilie; Jin, Xiaofeng; Zhang, Xianmin

    2016-09-10

    Photonic time stretch (PTS) has been intensively investigated in recent decades due to its potential application to ultra-wideband analog-to-digital conversion. A high-speed analog signal can be captured by an electronic analog-to-digital converter (ADC) with the help of the PTS technique, which slows down the speed of signal in the photonic domain. Unfortunately, the process of the time stretch is not linear due to the nonlinear modulation of the electro-optic intensity modulator in the PTS system, which means the undesired harmonics distortion. In this paper, we present an exact analytical model to fully characterize the harmonics generation in the PTS systems for the first time, to the best of our knowledge. We obtain concise and closed-form expressions for all harmonics of the PTS system with either a single-arm Mach-Zehnder modulator (MZM) or a push-pull MZM. The presented model can largely simplify the PTS system design and the system parameters estimation, such as system bandwidth, harmonics power, time-bandwidth product, and dynamic range. The correctness of the mathematic model is verified by the numerical and experimental results.

  14. Intermittent stretching induces fibrosis in denervated rat muscle.

    Science.gov (United States)

    Faturi, Fernanda M; Franco, Rúbia C; Gigo-Benato, Davilene; Turi, Andriette C; Silva-Couto, Marcela A; Messa, Sabrina P; Russo, Thiago L

    2016-01-01

    Stretching (St) has been used for treating denervated muscles. However, its effectiveness and safety claims require further study. Rats were divided into: (1) those with denervated (D) muscles, evaluated 7 or 15 days after sciatic nerve crush injury; (2) those with D muscles submitted to St during 7 or 15 days; and (3) those with normal muscles. Muscle fiber cross-sectional area, serial sarcomere number, sarcomere length, and connective tissue density were measured. MMP-2, MMP-9, TIMP-1, TGF-β1, and myostatin mRNAs were determined by real-time polymerase chain reaction. MMP-2 and MMP-9 activity was evaluated by zymography. Collagen I was localized using immunofluorescence. St did not prevent muscle atrophy due to denervation, but it increased fibrosis and collagen I deposition at day 15. St also upregulated MMP-9 and TGF-β1 gene expressions at day 7, and myostatin at day 15. Stretching denervated muscle does not prevent atrophy, but it increases fibrosis via temporal modulation of TGF-β1/myostatin and MMP-9 cascades. © 2015 Wiley Periodicals, Inc.

  15. A multireference perturbation study of the NN stretching frequency of trans-azobenzene in nπ* excitation and an implication for the photoisomerization mechanism.

    Science.gov (United States)

    Harabuchi, Yu; Ishii, Moe; Nakayama, Akira; Noro, Takeshi; Taketsugu, Tetsuya

    2013-02-14

    A multireference second-order perturbation theory is applied to calculate equilibrium structures and vibrational frequencies of trans-azobenzene in the ground and nπ* excited states, as well as the reaction pathways for rotation and inversion mechanism in the nπ* excited state. It is found that the NN stretching frequency exhibits a slight increase at the minimum energy structure in the nπ* state, which is explained by the mixing of the NN stretching mode with the CN symmetric stretching mode. We also calculate the NN stretching frequency at several selected structures along the rotation and inversion pathways in the nπ* state, and show that the frequency decreases gradually along the rotation pathway while it increases by ca. 300 cm(-1) along the inversion pathway. The frequencies and energy variations along the respective pathways indicate that the rotation pathway is more consistent with the experimental observation of the NN stretching frequency in nπ* excitation.

  16. Effect of stretching-based rehabilitation on pain, flexibility and muscle strength in dancers with hamstring injury: a single-blind, prospective, randomized clinical trial.

    Science.gov (United States)

    Kim, Giwon; Kim, Hyangsun; Kim, Woo K; Kim, Junesun

    2017-10-24

    Hamstring injuries commonly occur in mainstream sports and occupations that involve physical activity. We evaluated the effect of a stretching-based rehabilitation program on pain, flexibility, and strength in dancers with hamstring injuries. Sixteen Korean traditional dancers with unilateral hamstring injuries were included and randomly assigned to a rehabilitation or control group. The rehabilitation group received stretching-based rehabilitation for 8 weeks, which comprised simple static stretches and basic range of motion (ROM) exercises, such as static and active stretching, concentric and eccentric ROM training, and trunk stabilization exercises. The control group received conventional treatment with analgesics and physical therapy. Outcomes were assessed before and after the interventions in both groups by comparing the visual analog scale (VAS) score for pain, straight leg raise ROM test for hamstring muscle flexibility, and isometric strength test for hamstring muscle strength. Subjects who underwent rehabilitation showed significant improvements in VAS score for pain (p = 0.017) and ROM for flexibility (p flexibility and strength in patients with hamstring injury. The data indicate that a stretching-based rehabilitation program can help promote functional recovery from hamstring injury.

  17. The Efficacy of Dynamic Contract-Relax Stretching on Delayed-Onset Muscle Soreness Among Healthy Individuals: A Randomized Clinical Trial.

    Science.gov (United States)

    Xie, Yanfei; Feng, Beibei; Chen, Kedi; Andersen, Lars L; Page, Phil; Wang, Yuling

    2018-01-01

    To evaluate the efficacy of dynamic contract-relax stretching on delayed-onset muscle soreness (DOMS) in the calf muscle of healthy individuals. Randomized clinical trial. Research laboratory. Three groups of 16 healthy participants (n = 48) were recruited by convenience sampling. Three sets of resisted bilateral heel-raising exercises until exhaustion were conducted to initiate DOMS. Participants were randomly allocated into control group without any interventions, dynamic contract-relax stretching (DS), or static stretching (SS) groups. Dynamic contract-relax stretching and SS groups performed DS and SS, respectively, on the dominant leg twice a day for 5 consecutive days (before time points of outcome measurements at 24, 48, 72, 96, and 120 hours postexercise, respectively). Muscle soreness, lower leg girth, pressure pain threshold (PPT), range of motion (ROM), and muscle strength were measured before exercise, immediately after, and at 24, 48, 72, 96, and 120 hours postexercise. There was a significant effect of time in all outcome measures including muscle soreness, lower leg girth, PPT, ROM, and muscle strength; however, there were no significant group differences or group by time interactions. The effect of DS on relieving DOMS in the calf muscle is insignificant in this study. Further evidence is needed to prove the efficacy of DS on DOMS. Stretching is commonly recommended before and after exercise; however, this study showed no significant impact of DS or SS in treating DOMS.

  18. The Considere condition and rapid stretching of linear and branched polymer melts

    DEFF Research Database (Denmark)

    McKinley, Gareth H; Hassager, Ole

    1999-01-01

    , 81-110 (1998)] for prototypical branched melts we show that the critical strain to failure in rapid elongation of a rubbery material is intimately linked to the molecular topology of the chain, especially the degree of chain branching. The onset of necking instability is monotonically shifted......We analyze the onset of ''necking'' and subsequent filament failure during the transient uniaxial elongation of viscoelastic fluid samples in extensional rheometers. In the limit of rapid elongation (such that no molecular relaxation occurs), the external work applied is all stored elastically...... to larger Hencky strains as the number of branches is increased. Numerical computations at finite Deborah numbers also show that there is an optimal range of deformation rates over which homogeneous extensions can be maintained to large strain. We also consider other rapid homogeneous stretching...

  19. Effect of restorative yoga vs. stretching on diurnal cortisol dynamics and psychosocial outcomes in individuals with the metabolic syndrome: the PRYSMS randomized controlled trial.

    Science.gov (United States)

    Corey, Sarah M; Epel, Elissa; Schembri, Michael; Pawlowsky, Sarah B; Cole, Roger J; Araneta, Maria Rosario G; Barrett-Connor, Elizabeth; Kanaya, Alka M

    2014-11-01

    Chronic stimulation and dysregulation of the neuroendocrine system by stress may cause metabolic abnormalities. We estimated how much cortisol and psychosocial outcomes improved with a restorative yoga (relaxation) versus a low impact stretching intervention for individuals with the metabolic syndrome. We conducted a 1-year multi-center randomized controlled trial (6-month intervention and 6-month maintenance phase) of restorative yoga vs. stretching. Participants completed surveys to assess depression, social support, positive affect, and stress at baseline, 6 months and 12 months. For each assessment, we collected saliva at four points daily for three days and collected response to dexamethasone on the fourth day for analysis of diurnal cortisol dynamics. We analyzed our data using multivariate regression models, controlling for study site, medications (antidepressants, hormone therapy), body mass index, and baseline cortisol values. Psychosocial outcome measures were available for 171 study participants at baseline, 140 at 6 months, and 132 at 1 year. Complete cortisol data were available for 136 of 171 study participants (72 in restorative yoga and 64 in stretching) and were only available at baseline and 6 months. At 6 months, the stretching group had decreased cortisol at waking and bedtime compared to the restorative yoga group. The pattern of changes in stress mirrored this improvement, with the stretching group showing reductions in chronic stress severity and perseverative thoughts about their stress. Perceived stress decreased by 1.5 points (-0.4; 3.3, p=0.11) at 6 months, and by 2.0 points (0.1; 3.9, p=0.04) at 1 year in the stretching compared to restorative yoga groups. Post hoc analyses suggest that in the stretching group only, perceived increases in social support (particularly feelings of belonging), but not changes in stress were related to improved cortisol dynamics. We found significant decreases in salivary cortisol, chronic stress severity

  20. Acute Effects of the Different Intensity of Static Stretching on Flexibility and Isometric Muscle Force.

    Science.gov (United States)

    Kataura, Satoshi; Suzuki, Shigeyuki; Matsuo, Shingo; Hatano, Genki; Iwata, Masahiro; Yokoi, Kazuaki; Tsuchida, Wakako; Banno, Yasuhiro; Asai, Yuji

    2017-12-01

    Kataura, S, Suzuki, S, Matsuo, S, Hatano, G, Iwata, M, Yokoi, K, Tsuchida, W, Banno, Y, and Asai, Y. Acute effects of the different intensity of static stretching on flexibility and isometric muscle force. J Strength Cond Res 31(12): 3403-3410, 2017-In various fields, static stretching is commonly performed to improve flexibility, whereas the acute effects of different stretch intensities are unclear. Therefore, we investigated the acute effects of different stretch intensities on flexibility and muscle force. Eighteen healthy participants (9 men and 9 women) performed 180-second static stretches of the right hamstrings at 80, 100, and 120% of maximum tolerable intensity without stretching pain, in random order. The following outcomes were assessed as markers of lower limb function and flexibility: static passive torque (SPT), range of motion (ROM), passive joint (muscle-tendon) stiffness, passive torque (PT) at onset of pain, and isometric muscle force. Static passive torque was significantly decreased after all stretching intensities (p ≤ 0.05). Compared with before stretching at 100 and 120% intensities, ROM and PT were significantly increased after stretching (p ≤ 0.05), and passive stiffness (p = 0.05) and isometric muscle force (p ≤ 0.05) were significantly decreased. In addition, ROM was significantly greater after stretching at 100 and 120% than at 80%, and passive stiffness was significantly lower after 120% than after 80% (p ≤ 0.05). However, all measurements except SPT were unchanged after 80% intensity. There was a weak positive correlation between the intensities of stretching and the relative change for SPT (p ≤ 0.05), a moderate positive correlation with ROM (p ≤ 0.05), and a moderate positive correlation with passive stiffness (p ≤ 0.05). These results indicate that static stretching at greater intensity is more effective for increasing ROM and decreasing passive muscle-tendon stiffness.

  1. Stretch-induced intussuceptive and sprouting angiogenesis in the chick chorioallantoic membrane

    OpenAIRE

    Belle, Janeil; Ysasi, Alexandra; Bennett, Robert D.; Filipovic, Nenad; Imani Nejad, Mohammad; Trumper, David L.; Ackermann, Maximilian; Wagner, Willi; Tsuda, Akira; Konerding, Moritz A.; Mentzer, Steven J.

    2014-01-01

    Vascular systems grow and remodel in response to not only metabolic needs, but also mechanical influences as well. Here, we investigated the influence of tissue-level mechanical forces on the patterning and structure of the chick chorioallantoic membrane (CAM) microcirculation. A dipole stretch field was applied to the CAM using custom computer-controlled servomotors. The topography of the stretch field was mapped using finite element models. After 3 days of stretch, Sholl analysis of the CAM...

  2. Does acute passive stretching increase muscle length in children with cerebral palsy?

    Science.gov (United States)

    Theis, Nicola; Korff, Thomas; Kairon, Harvey; Mohagheghi, Amir A

    2013-01-01

    Children with spastic cerebral palsy experience increased muscle stiffness and reduced muscle length, which may prevent elongation of the muscle during stretch. Stretching performed either by the clinician, or children themselves is used as a treatment modality to increase/maintain joint range of motion. It is not clear whether the associated increases in muscle-tendon unit length are due to increases in muscle or tendon length. The purpose was to determine whether alterations in ankle range of motion in response to acute stretching were accompanied by increases in muscle length, and whether any effects would be dependent upon stretch technique. Eight children (6-14 y) with cerebral palsy received a passive dorsiflexion stretch for 5 × 20 s to each leg, which was applied by a physiotherapist or the children themselves. Maximum dorsiflexion angle, medial gastrocnemius muscle and fascicle lengths, and Achilles tendon length were calculated at a reference angle of 10 ° plantarflexion, and at maximum dorsiflexion in the pre- and post-stretch trials. All variables were significantly greater during pre- and post-stretch trials compared to the resting angle, and were independent of stretch technique. There was an approximate 10 ° increase in maximum dorsiflexion post-stretch, and this was accounted for by elongation of both muscle (0.8 cm) and tendon (1.0 cm). Muscle fascicle length increased significantly (0.6 cm) from pre- to post-stretch. The results provide evidence that commonly used stretching techniques can increase overall muscle, and fascicle lengths immediately post-stretch in children with cerebral palsy. © 2013.

  3. Knee Stretch Walking Method for Biped Robot: Using Toe and Heel Joints to Increase Walking Strides

    Science.gov (United States)

    Sato, Takahiko; Shimmyo, Shuhei; Nakazato, Miki; Mikami, Kei; Sato, Tomoya; Sakaino, Sho; Ohnishi, Kouhei

    This paper proposes a knee stretch walking method for biped robots; the method involves the use of the toes and heel joints to increase walking strides. A knee can be stretched by switching control variables. By a knee stretch walking with heel contacts to the ground and toe takeoffs from the ground, biped robots can increase their walking stride and speed. The validity of the proposed method is confirmed by simulation and experimental results.

  4. High Throughput Web Inspection System using Time-stretch Real-time Imaging

    OpenAIRE

    Kim, Chanju

    2013-01-01

    Photonic time-stretch is a novel technology that enables capturing of fast, rare and non-repetitive events. Therefore, it operates in real-time with ability to record over long period of time while having fine temporal resolution. The powerful property of photonic time-stretch has already been employed in various fields of application such as analog-to-digital conversion, spectroscopy, laser scanner and microscopy. Further expanding the scope, we fully exploit the time-stretch technology to d...

  5. Correlation of the Elastic Properties of Stretch Film on Unit Load Containment

    OpenAIRE

    Bisha, James Victor

    2012-01-01

    The purpose of this research was to correlate the applied material properties of stretch film with its elastic properties measured in a laboratory setting. There are currently no tools available for a packaging engineer to make a scientific decision on how one stretch film performs against another without applying the film. The system for stretch wrap comparison is mostly based on trial and error which can lead to a significant loss of product when testing a new film or shipping a new product...

  6. Mechanisms of pulmonary cyst pathogenesis in Birt-Hogg-Dube syndrome: The stretch hypothesis.

    Science.gov (United States)

    Kennedy, John C; Khabibullin, Damir; Henske, Elizabeth P

    2016-04-01

    Loss-of-function mutations in the folliculin gene (FLCN) on chromosome 17p cause Birt-Hogg-Dube syndrome (BHD), which is associated with cystic lung disease. The risk of lung collapse (pneumothorax) in BHD patients is 50-fold higher than in the general population. The cystic lung disease in BHD is distinctive because the cysts tend to be basilar, subpleural and lentiform, differentiating BHD from most other cystic lung diseases. Recently, major advances in elucidating the primary functions of the folliculin protein have been made, including roles in mTOR and AMPK signaling via the interaction of FLCN with FNIP1/2, and cell-cell adhesion via the physical interaction of FLCN with plakophilin 4 (PKP4), an armadillo-repeat containing protein that interacts with E-cadherin and is a component of the adherens junctions. In addition, in just the last three years, the pulmonary impact of FLCN deficiency has been examined for the first time. In mouse models, evidence has emerged that AMPK signaling and cell-cell adhesion are involved in alveolar enlargement. In addition, the pathologic features of human BHD cysts have been recently comprehensively characterized. The "stretch hypothesis" proposes that cysts in BHD arise because of fundamental defects in cell-cell adhesion, leading to repeated respiration-induced physical stretch-induced stress and, over time, expansion of alveolar spaces particularly in regions of the lung with larger changes in alveolar volume and at weaker "anchor points" to the pleura. This hypothesis ties together many of the new data from cellular and mouse models of BHD and from the human pathologic studies. Critical questions remain. These include whether the consequences of stretch-induced cyst formation arise through a destructive/inflammatory program or a proliferative program (or both), whether cyst initiation involves a "second hit" genetic event inactivating the remaining wild-type copy of FLCN (as is known to occur in BHD-associated renal cell

  7. Duration Dependent Effect of Static Stretching on Quadriceps and Hamstring Muscle Force

    Directory of Open Access Journals (Sweden)

    Leyla Alizadeh Ebadi

    2018-03-01

    Full Text Available The aim of this study was to determine the acute effect of static stretching on hamstring and quadriceps muscles’ isokinetic strength when applied for various durations to elite athletes, to investigate the effect of different static stretching durations on isokinetic strength, and finally to determine the optimal stretching duration. Fifteen elite male athletes from two different sport branches (10 football and five basketball participated in this study. Experimental protocol was designed as 17 repetitive static stretching exercises for hamstring and quadriceps muscle groups according to the indicated experimental protocols; ((A 5 min jogging; (B 5 min jogging followed by 15 s static stretching; (C 5 min jogging followed by 30 s static stretching; (D 5 min jogging, followed by static stretching for 45 s. Immediately after each protocol, an isokinetic strength test consisting of five repetitions at 60°/s speed and 20 repetitions at 180°/s speed was recorded for the right leg by the Isomed 2000 device. Friedman variance analysis test was employed for data analysis. According to the analyzes, it was observed that 5 min jogging and 15 s stretching exercises increased the isokinetic strength, whereas 30 and 45 s stretching exercises caused a decrease.

  8. EFFECTS OF DYNAMIC AND STATIC STRETCHING WITHIN GENERAL AND ACTIVITY SPECIFIC WARM-UP PROTOCOLS

    Directory of Open Access Journals (Sweden)

    Michael Samson

    2012-06-01

    Full Text Available The purpose of the study was to determine the effects of static and dynamic stretching protocols within general and activity specific warm-ups. Nine male and ten female subjects were tested under four warm-up conditions including a 1 general aerobic warm-up with static stretching, 2 general aerobic warm-up with dynamic stretching, 3 general and specific warm-up with static stretching and 4 general and specific warm-up with dynamic stretching. Following all conditions, subjects were tested for movement time (kicking movement of leg over 0.5 m distance, countermovement jump height, sit and reach flexibility and 6 repetitions of 20 metre sprints. Results indicated that when a sport specific warm-up was included, there was an 0.94% improvement (p = 0.0013 in 20 meter sprint time with both the dynamic and static stretch groups. No such difference in sprint performance between dynamic and static stretch groups existed in the absence of the sport specific warm-up. The static stretch condition increased sit and reach range of motion (ROM by 2.8% more (p = 0.0083 than the dynamic condition. These results would support the use of static stretching within an activity specific warm-up to ensure maximal ROM along with an enhancement in sprint performance

  9. 600 Volt Stretched Lens Array for Solar Electric Propulsion, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — ENTECH, Auburn, NASA, and others have recently developed a new space photovoltaic array called the Stretched Lens Array (SLA), offering unprecedented performance...

  10. Effects of hamstring stretching on passive muscle stiffness vary between hip flexion and knee extension maneuvers.

    Science.gov (United States)

    Miyamoto, N; Hirata, K; Kanehisa, H

    2017-01-01

    The purpose of this study was to examine whether the effects of hamstring stretching on the passive stiffness of each of the long head of the biceps femoris (BFl), semitendinosus (ST), and semimembranosus (SM) vary between passive knee extension and hip flexion stretching maneuvers. In 12 male subjects, before and after five sets of 90 s static stretching, passive lengthening measurements where knee or hip joint was passively rotated to the maximal range of motion (ROM) were performed. During the passive lengthening, shear modulus of each muscle was measured by ultrasound shear wave elastography. Both stretching maneuvers significantly increased maximal ROM and decreased passive torque at a given joint angle. Passive knee extension stretching maneuver significantly reduced shear modulus at a given knee joint angle in all of BFl, ST, and SM. In contrast, the stretching effect by passive hip flexion maneuver was significant only in ST and SM. The present findings indicate that the effects of hamstring stretching on individual passive muscles' stiffness vary between passive knee extension and hip flexion stretching maneuvers. In terms of reducing the muscle stiffness of BFl, stretching of the hamstring should be performed by passive knee extension rather than hip flexion. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Implementation of a controller for linear positioners applicable in optical fiber stretching

    International Nuclear Information System (INIS)

    Castrillo Piedra, Andres Rodolfo

    2014-01-01

    A low cost controller is implemented for linear positioners applicable in optic fiber stretching. The possibility of using a donated equipment is evaluated by the Escuela de Ingenieria Mecanica. The equipment is required by the non-linear photonic research laboratory (NLPR-LAB) for stretching of micro structured fiber. The process has required a slow and precise stretching, so the controllers must be precisely programmed to rotate the motors at different speeds. Donated equipment is evaluated to see if it is possible to use for fiber stretching [es